29EX

Cryo-EM structure of 3-methylcrotonyl- CoA carboxylase (MCC) complex (BC-engage BCCP state) from Mycobacterium smegmatis

This is a non-PDB format compatible entry.

Summary for 29EX

• Entry DOI: 10.2210/pdb29ex/pdb
• EMDB information: 57132
• Descriptor: Carboxyl transferase domain protein, biotin carboxylase, BIOTIN (3 entities in total)
• Functional Keywords: biotin carboxyalse, ligase
• Biological source: Mycolicibacterium smegmatis MC2 155; More
• Total number of polymer chains: 12
• Total formula weight: 751231.33

Authors

Yadav, A.,Geibel, S.R.J. (deposition date: 2026-03-09, release date: 2026-09-23)

Primary citation

Yadav, A.,Florea, B.I.,Geibel, S.
Structures of mycobacterial 3-methylcrotonyl-CoA carboxylase reveal carrier-domain translocation between catalytic sites.
Febs Lett., 2026

PubMed Abstract: 3-Methylcrotonyl-CoA carboxylase (MCC) catalyzes an essential step in leucine degradation. Here, we report two high-resolution cryo-EM structures of endogenous, biotin-bound Mycobacterium smegmatis AccA1-AccD1 MCC. The αβ complex adopts a canonical architecture with a hexameric carboxyltransferase core flanked by trimeric biotin carboxylase modules. The structures capture BCCP engaged at either the BC or CT active site, revealing long-range carrier-domain translocation. In the CT-engaged state, local BC-domain shifts disrupt the BC-site BCCP-interaction network, disfavoring BCCP rebinding. Unlike human MCC, no comparable CT-core remodeling is observed, suggesting distinct mechanisms of carrier-domain coordination.

PubMed: 42723463
DOI: 10.1002/1873-3468.70453

Experimental method

ELECTRON MICROSCOPY (2.9 Å)