Biology subjects

Kazmi, A. A.

Publications and source records attributed to Kazmi, A. A..

2 recordsLinked to original sources

bioRxiv2026

Cryo-EM reveals the central steps of mitochondrial complex III assembly and the cooperative assembly of supercomplex CIII2CIV

Mitochondrial complex III is the central component of the respiratory chain and is conserved across eukaryotes. Complex III is an obligate dimer which assembles through a stepwise mechanism, involving 20 subunits and other assembly factors. Defects in the assembly of complex III are associated with metabolic diseases. The assembly mechanism of complex III has long been investigated using biochemical approaches, which suggested a process where folded subunits are added sequentially and in parallel for the two protomers after dimerization. Our structural investigation of CIII2 assembly challenges these assumptions: we observe using cryo-EM that incorporation and folding of its subunits can be uncoupled (as we show for cytochrome c1) and that after dimerization the assembly of the complex does not proceed in parallel for the two protomers (as we show for the folding of the intermembrane space domain). Our structures also reveal the mechanism of formation of supercomplex CIII2CIV for non-vertebrates, intertwined with the assembly of CIII2. This work reshapes our knowledge of complex III assembly and proposes a generalizable model for the maturation of the complex, alongside a model for supercomplex formation that supports the cooperative assembly model. Furthermore, as the observed assembly steps cannot be predicted by AlphaFold, our work also showcases the central role of cryo-EM in the study of assembly mechanism of protein complexes.

molecular biology↗

bioRxiv2020

Effect of earthworms in removal and fate of Antibiotic resistant bacteria (ARB) and antibiotic resistant genes (ARG) during clinical laboratory wastewater treatment by vermifiltration

The wastewater treatment plants effluent has been implicated in the spread of antibiotic resistant bacteria (ARB) as these environment contains multiple selective pressures that may increase mutation rates, pathogen survivability, and induce gene transfer between bacteria. In lieu of this, the present study explored the dynamics of earthworm-microorganisms interactions on the treatment efficacy of clinical laboratory wastewater treatment by vermifiltration and the effect of earthworms in the fate of removal of pathogens and ARB. The results of the study showed that earthworms and VF associated microbial community had a significant effect on BOD and COD reduction (78-85%), pathogen removal (>99.9 %) and caused a significant shift in the prevalence pattern of ARB. Additionally, molecular profiling of ESBL (blaSHV, blaTEM and blaCTX-M), MRSA (mec-A) and Colistin (mcr-1) gene confirmed the probable mechanisms behind the resistance pattern. The microbial community diversity assists in the formation of biofilm, which helps in the removal of pathogens and results in a paradigm shift in the resistance profile of ARB and ARG, specifically most effective against drugs, targeting cell wall and protein synthesis inhibition like Ampicillin, Ticarcillin, Gentamicin and Chloramphenicol. These findings prove vermifiltration technology as a sustainable and natural treatment technology for clinical laboratory wastewater.

ecology↗