8WTB

Crystal structure of McsA/McsB complex truncated by chymotrypsin

Summary for 8WTB

• Entry DOI: 10.2210/pdb8wtb/pdb
• Descriptor: Protein-arginine kinase, Protein-arginine kinase activator protein, ZINC ION (3 entities in total)
• Functional Keywords: protein-arginine kinase, zinc-coordination motif, activator, transferase
• Biological source: Bacillus subtilis subsp. subtilis str. 168; More
• Total number of polymer chains: 4
• Total formula weight: 126094.61

Authors

Arifuzzaman, M.,Kwon, E.,Kim, D.Y. (deposition date: 2023-10-18, release date: 2024-05-08, Last modification date: 2024-11-06)

Primary citation

Arifuzzaman, M.,Kwon, E.,Kim, D.Y.
Structural insights into the regulation of protein-arginine kinase McsB by McsA.
Proc.Natl.Acad.Sci.USA, 121:e2320312121-e2320312121, 2024

PubMed Abstract: In gram-positive bacteria, phosphorylated arginine functions as a protein degradation signal in a similar manner as ubiquitin in eukaryotes. The protein-arginine phosphorylation is mediated by the McsAB complex, where McsB possesses kinase activity and McsA modulates McsB activity. Although and are regulated within the same operon, the role of McsA in kinase activity has not yet been clarified. In this study, we determined the molecular mechanism by which McsA regulates kinase activity. The crystal structure of the McsAB complex shows that McsA binds to the McsB kinase domain through a second zinc-coordination domain and the subsequent loop region. This binding activates McsB kinase activity by rearranging the catalytic site, preventing McsB self-assembly, and enhancing stoichiometric substrate binding. The first zinc-coordination and coiled-coil domains of McsA further activate McsB by reassembling the McsAB oligomer. These results demonstrate that McsA is the regulatory subunit for the reconstitution of the protein-arginine kinase holoenzyme. This study provides structural insight into how protein-arginine kinase directs the cellular protein degradation system.

PubMed: 38625935
DOI: 10.1073/pnas.2320312121

Experimental method

X-RAY DIFFRACTION (2.9 Å)