6tv6 | pdb_00006tv6
Octameric McsB from Bacillus subtilis.
Structural highlights
Function[MCSB_BACSU] Catalyzes the specific phosphorylation of arginine residues in a large number of proteins. Is part of the bacterial stress response system, where it is involved in regulating the global heat shock repressor CtsR; phosphorylates arginine residues in the winged helix-turn-helix domain of CtsR, thereby preventing its binding to DNA and consequently inducing the expression of repressed genes. The transcriptional repressor HrcA, the chaperone GroEL, the unfoldase ClpC, together with several ribosomal subunits, represent other physiological targets of McsB under stress conditions. Protein arginine phosphorylation has a physiologically important role and is involved in the regulation of many critical cellular processes, such as protein homeostasis, motility, competence, and stringent and stress responses, by regulating gene expression and protein activity. Functions as an adapter whose kinase activity is required for ClpCP-mediated degradation of CtsR during heat stress. Is required for the delocalization of competence proteins from the cell poles, probably via a role in the degradation of anchor proteins.[1] [2] [3] [4] [5] Publication Abstract from PubMedIn Gram-positive bacteria, the McsB protein arginine kinase is central to protein quality control, labeling aberrant molecules for degradation by the ClpCP protease. Despite its importance for stress response and pathogenicity, it is still elusive how the bacterial degradation labeling is regulated. Here, we delineate the mechanism how McsB targets aberrant proteins during stress conditions. Structural data reveal a self-compartmentalized kinase, in which the active sites are sequestered in a molecular cage. The 'closed' octamer interconverts with other oligomers in a phosphorylation-dependent manner and, unlike these 'open' forms, preferentially labels unfolded proteins. In vivo data show that heat-shock triggers accumulation of higher order oligomers, of which the octameric McsB is essential for surviving stress situations. The interconversion of open and closed oligomers represents a distinct regulatory mechanism of a degradation labeler, allowing the McsB kinase to adapt its potentially dangerous enzyme function to the needs of the bacterial cell. McsB forms a gated kinase chamber to mark aberrant bacterial proteins for degradation.,Hajdusits B, Suskiewicz MJ, Hundt N, Meinhart A, Kurzbauer R, Leodolter J, Kukura P, Clausen T Elife. 2021 Jul 30;10. pii: 63505. doi: 10.7554/eLife.63505. PMID:34328418[6] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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