Biology subjects

Zheng, H.

Publications and source records attributed to Zheng, H..

At least 253 records · Page 14Linked to original sources

bioRxiv2020

Improved design and analysis of practical minimizers

MotivationMinimizers are methods to sample k-mers from a sequence, with the guarantee that similar set of k-mers will be chosen on similar sequences. It is parameterized by the k-mer length k, a window length w and an order on the k-mers. Minimizers are used in a large number of softwares and pipelines to improve computation efficiency and decrease memory usage. Despite the methods popularity, many theoretical questions regarding its performance remain open. The core metric for measuring performance of a minimizer is the density, which measures the sparsity of sampled k-mers. The theoretical optimal density for a minimizer is 1/w, provably not achievable in general. For given k and w, little is known about asymptotically optimal minimizers, that is minimizers with density O(1/w). ResultsWe derive a necessary and sufficient condition for existence of asymptotically optimal minimizers. We also provide a randomized algorithm, called the Miniception, to design minimizers with the best theoretical guarantee to date on density in practical scenarios. Constructing and using the Miniception is as easy as constructing and using a random minimizer, which allows the design of efficient minimizers that scale to the values of k and w used in current bioinformatics software programs. AvailabilityReference implementation of the Miniception and the codes for analysis can be found at https://github.com/kingsford-group/miniception. Contactgmarcais@cs.cmu.edu

bioinformatics↗

bioRxiv2020

A genome-wide association study finds genetic variants associated with neck or shoulder pain in UK Biobank

BackgroundCommon types of musculoskeletal conditions include pain in the neck and shoulder areas. This study seeks to identify the genetic variants associated with neck or shoulder pain based on a genome-wide association approach using 203,309 subjects from the UK Biobank cohort and look for replication evidence from the Generation Scotland: Scottish Family Health Study (GS:SFHS) and TwinsUK. MethodsCases in the UK Biobank were determined by a question which asked the participants if they had experienced pain in the neck or shoulder in the previous month influencing daily activities. Controls were the UK Biobank participants who reported no pain anywhere in the last month. A genome-wide association study was performed adjusting for age, sex, BMI and 9 population principal components. Significant and independent genetic variants were then sent to GS:SFHS and TwinsUK for replication. ResultsWe identified 3 genetic loci that were associated with neck or shoulder pain in the UK Biobank samples. The most significant locus was in an intergenic region in chromosome 17, rs12453010, having P = 1.66 x 10-11. The second most significant locus was located in the FOXP2 gene in chromosome 7 with P = 2.38 x 10-10 for rs34291892. The third locus was located in the LINC01572 gene in chromosome 16 with P = 4.50 x 10-8 for rs62053992. In the replication stage, among 4 significant and independent genetic variants, rs2049604 in the FOXP2 gene and rs62053992 in the LINC01572 gene were weakly replicated in GS:SFHS (P = 0.0240 and P = 0.0202, respectively). None of the single nucleotide polymorphisms (SNPs) were replicated in the TwinsUK cohort (P > 0.05). ConclusionsWe have identified 3 loci associated with neck or shoulder pain in the UK Biobank cohort, two of which were weakly supported in a replication cohort. Further evidence is needed to confirm their roles in neck or shoulder pain. SignificanceThis is the first genome-wide association study on neck or shoulder pain. We have identified 3 genetic loci (an intergenic region in chromosome 17, the FOXP2 gene in chromosome 7, and the LINC01572 gene in chromosome 16) that are associated with neck or shoulder pain using the UK Biobank cohort, among which the FOXP2 gene and the LINC01572 gene were weakly replicated by the Generation Scotland: Scottish Family Health Study (P < 0.05). The SNP heritability was 0.11, indicating neck or shoulder pain is a heritable trait. The tissue expression analysis suggested that neck or shoulder pain was related to multiple brain tissues, indicating the involvement of neuron function. The results will inform further research in the characterisation of the mechanisms of neck or shoulder pain.

genetics↗

bioRxiv2020

PD-L1 upregulation by IFN-α/γ-mediated Stat1 suppresses anti-HBV T cell response

Programmed death ligand 1 (PD-L1) has been recently shown to be a major obstacle to antiviral immunity by binding to its receptor programmed death 1 (PD-1) on specific IFN-{gamma} producing T cells in chronic hepatitis B. Currently, IFN- is widely used to treat hepatitis B virus(HBV) infection, but its antiviral effect vary greatly and the mechanism is not totally clear. We found that IFN-/{gamma} induced a marked increase of PD-L1 expression in hepatocytes. Signal and activators of transcription (Stat1) was then identified as a major transcription factor involved in IFN-/{gamma}-mediated PD-L1 elevation both in vitro and in mice. Blockage of the PD-L1/PD-1 interaction by a specific mAb greatly enhanced HBV-specific T cell activity by the gp96 adjuvanted therapeutic vaccine, and promoted HBV clearance in HBV transgenic mice. Our results demonstrate the IFN-/{gamma}-Stat1-PD-L1 axis plays an important role in mediating T cell hyporesponsiveness and inactivating liver-infiltrating T cells in the hepatic microenvironment. These data raise further potential interest in enhancing the anti-HBV efficacy of IFN- and therapeutic vaccines.

molecular biology↗

bioRxiv2019

Endothelial JAK2V617F mutation leads to thrombosis, vasculopathy, and cardiomyopathy in a murine model of myeloproliferative neoplasm

RationalThe myeloproliferative neoplasms (MPNs) are clonal hematological malignancies characterized by hematopoietic stem cell expansion and overproduction of mature blood cells. Cardiovascular complications are the leading cause of morbidity and mortality in patients with MPNs. The acquired kinase mutation JAK2V617F plays a central role in these disorders. Mechanisms responsible for cardiovascular dysfunction in MPNs are not fully understood, limiting the effectiveness of current treatment. ObjectiveVascular endothelial cells (ECs) play critical roles in the regulation of hemostasis and thrombosis. ECs carrying the JAK2V617F mutation can be detected in patients with MPNs. The goal of this study was to test the hypothesis that the JAK2V617F mutation alters endothelial function to promote cardiovascular complications in patients with MPNs. Methods and ResultsWe employed murine models of MPN in which the JAK2V617F mutation is expressed in specific cell lineages. When JAK2V617F is expressed in both blood cells and vascular ECs, the mice developed MPN and spontaneous, age-related dilated cardiomyopathy with an increased risk of sudden death as well as a prothrombotic and vasculopathy phenotype on histology evaluation. We showed that JAK2V617F-mutant ECs are required for this cardiovascular disease phenotype and the mutation can alter endothelial cell function. Finally, in a more therapeutically oriented approach, we demonstrated that transplantation with wild-type donor marrow cells can improve cardiac function by reversing the left ventricle remodeling process in this JAK2V617F-positive MPN murine model. ConclusionsThese findings suggest that the JAK2V617F mutation alters vascular endothelial function to promote cardiovascular complications in MPNs. Therefore, targeting the MPN vasculature represents a promising new therapeutic strategy for patients with MPNs.

molecular biology↗

bioRxiv2019

Finding ranges of optimal transcript expression quantification in cases of non-identifiability

Current expression quantification methods suffer from a fundamental but under-characterized type of error: the most likely estimates for transcript abundances are not unique. This means multiple estimates of transcript abundances generate the observed RNA-seq reads with equal likelihood, and the underlying true expression cannot be determined. This problem is called non-identifiability for probabilistic models, and is further exacerbated by incomplete reference transcriptome. That is, reads may be sequenced from unannotated expressed transcripts. Graph quantification is a generalization to transcript quantification, accounting for the reference incompleteness by allowing exponentially many unannotated transcripts to express reads. We propose methods to calculate a "confidence range of expression" for each transcript, representing its possible abundance across equally optimal estimates for both quantification models. This range informs both whether a transcript has potential estimation error due to non-identifiability and the extent of the error. Applying our methods to the Human Body Map data, we observe 35%-50% of transcripts potentially suffer from inaccurate quantification caused by non-identifiability. When comparing the expression between isoforms in one sample, we find that the degree of inaccuracy of 20%-47% transcripts can be so large that the ranking of expression between the transcript and its sibling isoforms cannot be determined. When comparing the expression of a transcript between two groups of RNA-seq samples in differential expression analysis, we observe that the majority of detected differentially expressed transcripts are reliable with a few exceptions after considering the ranges of the optimal expression estimates. The code for computing the range of expression is available at https://github.com/Kingsford-Group/subgraphquant. The code for the involved analyses is available at https://github.com/Kingsford-Group/subgraphquantanalysis.

bioinformatics↗

bioRxiv2019

A portable and cost-effective microfluidic system for massively parallel single-cell transcriptome profiling

Single-cell technologies are becoming increasingly widespread and have been revolutionizing our understanding of cell identity, state, diversity and function. However, current platforms can be slow to apply to large-scale studies and resource-limited clinical arenas due to a variety of reasons including cost, infrastructure, sample quality and requirements. Here we report DNBelab C4 (C4), a negative pressure orchestrated, portable and cost-effective device that enables high-throughput single-cell transcriptional profiling. C4 system can efficiently allow discrimination of species-specific cells at high resolution and dissect tissue heterogeneity in different organs, such as murine lung and cerebral cortex. Finally, we show that the C4 system is comparable to existing platforms but has huge benefits in cost and portability and, as such, it will be of great interest for the wider scientific community.

genomics↗

bioRxiv2019

Golden pompano genome and embryo transcriptome shed light on regulation of minor ZGA gene on heart and vascular development

BACKGROUNDAngiogenesis is closely associated with angiogenesis-dependent diseases including cancers and ocular diseases. Anti-angiogenic therapeutics have been focusing on the (VEGF)/VEGFR signaling axis. However, the clinical resistance, high cost and frequent administration of anti-VEGF drugs make it urgent to discover novel angiogenic pathways.VE-PTP (ptprb) is a novel target with great anti-angiogenic potential. However, it is unclear whether upstream signaling pathways targeting VE-PTP exist in angiogenesis. METHODSWhole genome and embryo transcriptome sequencing were applied to discover the new gene nxhl. Transgenic zebrafish model, morpholino knockdown and small interfering RNA were used to explore the role of nxhl in angiogenesis both in vitro and in vivo. RNA pulldown, RIP and ChIRP-MS were used to identify interactions between RNA and protein. RESULTSWe discovered a novel zebrafish gene nxhl which is a homologue of the conserved gene nxh that co-expressed with some key genes essential for embryo development in vertebrate. Nxhl deletion causes angiogenesis defects in embryo. Moreover, nxhl is essential to mediate effects of angiogenesis in vivo and in vitro, and ptprb depletion duplicates the phenotypes of nxhl deficiency. Importantly, nxhl acts upstream of ptprb and regulates many extreme important ptprb-linked angiogenic genes by targeting VE-PTP (ptprb) through interactions with NCL. Notably, nxhl deletion decreases the phosphorylation of NCL T76 and increases the acetylation of NCL K88, suggesting nxhl may regulate downstream VE-PTP signaling pathways by mediation of NCL posttranslational modification. This is the first description of the interaction between nxhl and NCL, NCL and VE-PTP (ptprb), uncovering a novel nxhl-NCL-VE-PTP signaling pathway on angiogenesis regulation. CONCLUSIONSOur study identifies nxhl controlling angiogenesis by targeting VE-PTP through interactions with NCL, uncovering novel upstream controllers of VE-PTP. This nxhl-NCL-VE-PTP pathway may be a therapeutic target in the treatment of angiogenesis-dependent diseases. Clinical PerspectiveO_ST_ABSWhat Is New?C_ST_ABSO_LIWe report a novel nxhl-NCL-VE-PTP signaling pathway that controls angiogenesis. C_LIO_LIWe for the first time demonstrate that nxhl interacts with NCL which simultaneously binds to VE-PTP that plays key roles on EC adherens junction, integrity and vascular homeostasis. C_LIO_LINxhl also controls some other crucial VE-PTP-linked downstream angiogenic genes (such as Tie2, VEGFaa, VEGFR2, Erbb2, S1pr1 and Hey2) which explain the phenotypes induced by the nxhl deficiency. C_LIO_LIOur study indicates the key role of nxhl on controlling angiogenesis as an upstream regulator of VE-PTP. C_LI What Are the Clinical Implications?O_LIThere are several ongoing researches investigating the utility of VE-PTP or NCL inhibitors on treatment of angiogenesis-dependent diseases including a range of cancers and nonneoplastic diseases, such as AMD, DME, RA and atherosclerosis. C_LIO_LITargeting the nxhl-NCL-VE-PTP pathway may facilitate therapeutic angiogenesis in patients with cancers or ocular diseases such as DME. C_LIO_LIOur study highlights the great potential of nxhl on anti-angiogenic therapeutics by targeting VE-PTP. C_LI

genomics↗

bioRxiv2019

CIC is a Critical Regulator of Neuronal Differentiation

Capicua (CIC), a member of the high mobility group (HMG)-box superfamily of transcriptional repressors, is frequently mutated in human oligodendrogliomas. But its function in brain development and tumorigenesis remains poorly understood. Here, we report that brain-specific deletion of Cic compromises developmental transition of neuroblast to immature neurons in mouse hippocampus and compromises normal neuronal differentiation. Combined gene expression and ChIP-seq analyses identified VGF as an important CIC-repressed transcriptional surrogates involved in neuronal lineage regulation. Aberrant VGF expression promotes neural progenitor cell proliferation by suppressing their differentiation. Mechanistically, we demonstrated that CIC represses VGF expression by tethering SIN3-HDAC to form a transcriptional corepressor complex. Mass spectrometry analysis of CIC-interacting proteins further identified BRG1 containing mSWI/SNF complex of which function is necessary for transcriptional repression by CIC. Together, this study uncovers a novel regulatory pathway of CIC-dependent neuronal differentiation and provides molecular insights into the etiology of CIC-dependent brain tumors.

cell biology↗

bioRxiv2019

A general quantitative relation linking bacterial cell growth and the cell cycle

The foundation of bacterial cell cycle studies has long resided in two interconnected dogmas between biomass growth, DNA replication, and cell division during exponential growth: the SMK growth law that relates cell mass (a measure of cell size) to growth rate1, and Donachies hypothesis of a growth-rate-independent initiation mass2. These dogmas have spurred many efforts to understand their molecular bases and physiological consequences3-12. Most of these studies focused on fast-growing cells, with doubling times shorter than 60 min. Here, we systematically studied the cell cycle of E. coli for a broad range of doubling times (24 min to over 10 hr), with particular attention on steady-state growth. Surprisingly, we observed that neither dogma held across the range of growth rates examined. In their stead, a new linear relation unifying the slow- and fast-growth regimes was revealed between the cell mass and the number of cell divisions it takes to replicate and segregate a newly initiated pair of replication origins. This and other findings in this study suggest a single-cell division model, which not only reproduces the bulk relations observed but also recapitulates the adder phenomenon established recently for stochastically dividing cells13-15. These results allowed us to develop quantitative insight into the bacterial cell cycle, providing a firm new foundation for the study of bacterial growth physiology.

microbiology↗

bioRxiv2019

Double asymmetric percolation drives a quadruple transition in sexual contact networks

Since 2007, ZIKV outbreaks have been occurring around the world. While ZIKV is mainly spread by mosquito vectors, transmission via sex activities enables the virus to spread in regions without mosquito vectors. Modeling the patterns of ZIKV outbreak in these regions remain challenging. We consider age as an asymmetric factor in transmitting ZIKV, in addition to gender as seen in previous literature, and modify the graph structure for better modeling of such patterns. We derived our results by both solving the underlying differential equations and simulation on population graph. Based on a double asymmetric percolation process on sexual contact networks. we discovered a quadruple ZIKV epidemic transition. Moreover, we explored the double asymmetric percolation on scale-free networks. Our work provides more insight into the ZIKV transmission dynamics through sexual contact networks, which may potentially provide better public health control and prevention means in a ZIKV outbreak.

bioinformatics↗

bioRxiv2019

Efficient multiplex genome editing using CRISPR-Mb3Cas12a in mice

Despite many advantages over Cas9, Cas12a has not been widely used in genome editing in mammalian cells largely due to its strict requirement of the TTTV protospacer adjacent motif (PAM) sequence. Here, we report that Mb3Cas12a (Moraxella bovoculi AAX11_00205) could edit the genome in murine zygotes independent of TTTV PAM sequences and with minimal on-target mutations and close to 100% editing efficiency when crRNAs of 23nt spacers were used.\n\nSummary statementCRISPR-Mb3Cas12a can target a broader range of sequences in murine zygotes compared to AsCas12a and LbCas12a, and has lower on-target effects than Cas9 and high overall knock-in efficiency.

genomics↗

bioRxiv2019

Shotgun Metagenomics of 361 elderly women reveals gut microbiome change in bone mass loss

Bone mass loss contributes to the risk of bone fracture in the elderly. Many factors including age, obesity, estrogen and diet, are associated with bone mass loss. Mice studies suggest that the intestinal microbiome might influence the bone mass by regulating the immune system, however there has been little evidence from human studies. We have recruited 361 Chinese elderly women to collect data for a metagenomic-wide association study (MWAS) to investigate the influence of the gut microbiome on bone health. Gut microbiome data were produced using BGISEQ500 sequencing, BMD was calculated using Hologic dual energy X-ray machine, BMI (Body Mass Index) and age were also provided. This therefore data allows exploration of gut microbiome diversity and links to bone mass loss, as well as microbial species and modules as markers for bone mineral density. Making these data potentially useful in studying the role the gut microbiota might play in bone mass loss and offering exploration into the bone mass loss process.

microbiology↗

bioRxiv2019

Evolution of satellite plasmids can stabilize the maintenance of newly acquired accessory genes in bacteria

Plasmids play a principal role in the spread of antibiotic resistance and other traits by horizontal gene transfer in bacteria. However, newly acquired plasmids generally impose a fitness burden on a cell, and they are lost from a population rapidly if there is not selection to maintain a unique function encoded on the plasmid. Mutations that ameliorate this fitness cost can sometimes eventually stabilize a plasmid in a new host, but they typically do so by inactivating some of its novel accessory genes. In this study, we identified an additional evolutionary pathway that can prolong the maintenance of newly acquired genes encoded on a plasmid. We discovered that propagation of an RSF1010-based IncQ plasmid in Escherichia coli often generated satellite plasmids with spontaneous deletions of accessory genes and genes required for plasmid replication. These smaller plasmid variants are nonautonomous genetic parasites. Their presence in a cell drives down the copy number of full-length plasmids, which reduces the burden from the accessory genes without eliminating them entirely. The evolution of satellite plasmids may be favored relative to other plasmid fates because they give a more immediate fitness advantage to a cells progeny and because the organization of IncQ plasmids makes them particularly prone to certain deletions during replication. Satellite plasmids also evolved in Snodgrassella alvi colonizing the honey bee gut, suggesting that this mechanism may broadly contribute to the importance of IncQ plasmids as agents of bacterial gene transfer in nature.\n\nSignificance StatementPlasmids are multicopy DNA elements found in bacteria that replicate independently of a cells chromosome. The spread of plasmids carrying antibiotic-resistance genes to new bacterial pathogens is a challenge for treating life-threatening infections. Often plasmids or their accessory genes encoding unique functions are lost soon after transfer into a new cell because they impose a fitness burden. We report that a family of transmissible plasmids can rapidly evolve satellite plasmids that replicate as genetic parasites of the original plasmid. Satellite plasmid formation reduces the burden from the newly acquired genes, which may enable them to survive intact for longer after transfer into a new cell and thereby contribute to the spread of antibiotic resistance and other traits within bacterial populations.

microbiology↗

bioRxiv2019

The rs6505162 C>A polymorphism in the miRNA-423 gene exhibits a protective element of coronary artery in a southern Chinese population with Kawasaki disease

BackgroundManifesting as acute rash, fever and vasculitis, belonging to autoimmune syndrome, Kawasaki disease(KD) is prone to occur in infants and young children. Males and females is affected by KD at a ratio of 1.4 to 1.7: 1. KD is known to own many common clinical manifestations and complications, like coronary artery lesion(CAL) and coronary artery aneurysm(CAA). Polymorphisms of the rs6505162 locus in the miRNA-423 gene are associated with enhancive susceptibility to coronary artery disease and the alterations of the four cytokines IL-4., IL-10, IL-21, IL-22 in the early stages of diabetes. However, no researcher has reported whether rs6505162 is related to KD susceptibility or no. Therefore, we carried out the trial concentrating on the connection between miRNA-423 rs6505162 C>A polymorphism and KD susceptibility.\n\nMethodsTo obtain the genotypes of rs6505162 in objects enrolled by 532 KD children and 623 control, we applied Taqman real-time PCR and all statistical analyses was carried out by SAS.\n\nResultsThe comparison between all cases and all controls hinted that the rs6505162C>A polymorphism has no relationship with KD susceptibility. Nevertheless, a subgroup analysis revealed that the CA/AA genotypes of rs6505162 could reduce the occurrence of CAA (Adjusted age and gender odds ratio=1.30, 95%CI=1.02-1.67, P=0.037) and CAL (Adjusted OR=1.56, 95%CI=1.19-2.03, P=0.001)in KD patients.\n\nConclusionOur final results stated clearly that miRNA-423 rs6505162 polymorphism appears to be a protective element of CAL and CAA in southern Chinese suffers with KD.

genetics↗

bioRxiv2019

Volumetric two-photon imaging in live cells and embryos via axially gradient excitation

Two-photon microscopy(TPM) that features subcellular resolution, intrinsic optical sectioning ability, and deep penetration in sample is a powerful tool of bioimaging. However, the process of layer-by-layer scanning to form a 3D image inherently limits the volumetric imaging speed and significantly increases the phototoxicity. Here we develop a gradient TPM technique that enables rapid volumetric imaging by only acquiring two 2D images. By sequentially exciting the specimen with two axially elongated two-photon beams with complementary gradient intensities, the axial positions of fluorophores can be decoded from the intensity ratio of the paired images. We achieve an axial localization accuracy of 0.728 {+/-} 0.657 m, which is sufficient for rapid 3D subcellular imaging. We demonstrate the flexibility of the gradient TPM on a variety of sparsely labelled samples, including bead phantoms, mouse brain tissues, live macrophages and live nematode embryos. The results show that, compared with conventional TPM, the 3D imaging speed increases 6 folds while the photobleaching and photodamage are extremely reduced.

bioengineering↗

bioRxiv2019

A Chemical Probe of CARM1 Alters Epigenetic Plasticity against Breast Cancer Cell Invasion

CARM1 is a cancer-relevant protein arginine methyltransferase that regulates many aspects of transcription. Its pharmacological inhibition is a promising anti-cancer strategy. Here SKI-73 is presented as a CARM1 chemical probe with pro-drug properties. SKI-73 can rapidly penetrate cell membranes and then be processed into active inhibitors, which are retained intracellularly with 10-fold enrichment for days. These compounds were characterized for their potency, selectivity, modes of action, and on-target engagement. SKI-73 recapitulates the effect of CARM1 knockout against breast cancer cell invasion. Single-cell RNA-seq analysis revealed that the SKI-73-associated reduction of invasiveness act via altering epigenetic plasticity and suppressing the invasion-prone subpopulation. Interestingly, SKI-73 and CARM1 knockout alter the epigenetic plasticity with remarkable difference, arguing distinct modes of action between the small-molecule and genetic perturbation. We therefore discovered a CARM1-addiction mechanism of cancer metastasis and developed a chemical probe to target this process.

biochemistry↗

bioRxiv2019

In vivo structure of the Legionella type II secretion system by electron cryotomography

The type II secretion system (T2SS) is a multi-protein envelope-spanning assembly that translocates a wide range of virulence factors, enzymes and effectors through the outer membrane (OM) of many Gram-negative bacteria. Here, using electron cryotomography and subtomogram averaging methods, we present the first in situ structure of an intact T2SS, imaged within the human pathogen Legionella pneumophila. Although the T2SS has only limited sequence and component homology with the evolutionarily-related Type IV pilus (T4P) system, we show that their overall architectures are remarkably similar. Despite similarities, there are also differences, including for instance that the T2SS-ATPase complex is usually present but disengaged from the inner membrane, the T2SS has a much longer periplasmic vestibule, and it has a short-lived flexible pseudopilus. Placing atomic models of the components into our ECT map produced a complete architectural model of the intact T2SS that provides new insights into the structure and function of its components, its position within the cell envelope, and the interactions between its different subcomplexes. Overall, these structural results strongly support the piston model for substrate extrusion.

microbiology↗

bioRxiv2019

Structural basis of HMCES interactions with DNA reveals multivalent substrate recognition

HMCES can covalently crosslink to abasic sites in single-stranded DNA at stalled replication forks to prevent genome instability. Here, we report crystal structures of the HMCES SRAP domain in complex with DNA-damage substrates, revealing interactions with both single-stranded and duplex segments of 3 overhang DNA. HMCES may also bind gapped DNA and 5 overhang structures to align single stranded abasic sites for crosslinking to the conserved Cys2 of its catalytic triad.

biochemistry↗