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Biology subjects

Zhuang, N.

Publications and source records attributed to Zhuang, N..

2 recordsLinked to original sources

The crystal and cryo-EM structures of PLCγ2 reveal dynamic inter-domain recognitions in autoinhibition

Abstract/SummaryPhospholipase C gamma 2 (PLC{gamma}2) plays important roles in cell signaling downstream of various membrane receptors. PLC{gamma}2 contains a multi-domain inhibitory region critical for its regulation, while it has remained unclear how these domains contribute to PLC{gamma}2 activity modulation. Here we determined three structures of human PLC{gamma}2 in autoinhibited states, which reveal dynamic interactions at the autoinhibition interface, involving the conformational flexibility of the SH3 domain in the inhibitory region, and its previously unknown interaction with a C-terminal helical domain in the core region. We also determined a structure of PLC{gamma}2 bound to the kinase domain of fibroblast growth factor receptor 1 (FGFR1), which demonstrates the recognition of FGFR1 by the nSH2 domain in the inhibitory region of PLC{gamma}2. Our results provide new structural insights into PLC{gamma}2 regulation that will facilitate future mechanistic studies to understand the entire activation process.

biochemistry↗

Structural basis for transcription initiation by bacterial ECF σ factors

Bacterial RNA polymerase employs extra-cytoplasmic function (ECF) {sigma} factors to regulate context-specific gene expression programs. Despite being the most abundant and divergent {sigma} factor class, the structural basis of ECF {sigma} factor-mediated transcription initiation remains unknown. Here, we determine a crystal structure of Mycobacterium tuberculosis (Mtb) RNAP holoenzyme comprising an RNAP core enzyme and the ECF {sigma} factor {sigma}H ({sigma}H-RNAP) at 2.7 [A], and solve another crystal structure of a transcription initiation complex of Mtb {sigma}H-RNAP ({sigma}H-RPo) comprising promoter DNA and an RNA primer at 2.8 [A]. The two structures together reveal the interactions between {sigma}H and RNAP that are essential for {sigma}H-RNAP holoenzyme assembly as well as the interactions between {sigma}H-RNAP and promoter DNA responsible for stringent promoter recognition and for promoter unwinding. Our study establishes that ECF {sigma} factors and primary {sigma} factors employ distinct mechanisms for promoter recognition and for promoter unwinding.

microbiology↗