Crystal structures of Mycobacterial MeaB and MMAA-like GTPases
The methylmalonyl Co-A mutase-associated GTPase MeaB from Methylobacterium extorquens is involved in glyoxylate regulation and required for growth. In humans, mutations in the homolog methylmalonic aciduria associated protein (MMAA) cause methylmalonic aciduria, which is often fatal. The central role of MeaB from bacteria to humans suggests that MeaB is also important in other, pathogenic bacteria such as Mycobacterium tuberculosis. However, the identity of the mycobacterial MeaB homolog is presently unclear. Here, we identify the M. tuberculosis protein Rv1496 and its homologs in M. smegmatis and M. thermoresistibile as MeaB. The crystal structures of all three homologs are highly similar to MeaB and MMAA structures and reveal a characteristic three-domain homodimer with GDP bound in the G domain active site. A structure of Rv1496 obtained from a crystal grown in the presence of GTP exhibited electron density for GDP, suggesting GTPase activity. These structures identify the mycobacterial MeaB and provide a structural framework for therapeutic targeting of M. tuberculosis MeaB.
KeywordsMeaB Metallochaperone Methylmalonic aciduria associated protein MMAA Mycobacterium Ras-like GTPase Structural genomics Tuberculosis
Advanced Light Source
Atomic property force
Guanosine 5′ triphosphate
Immobilized metal ion affinity chromatography
Methylmalonyl aciduria associated protein A
Protein Data Bank
Sleeping beauty mutase
Seattle Structural Genomics Center for Infectious Disease
The authors thank the whole SSGCID team. This research was funded with federal funds from the National Institute of Allergy and Infectious Diseases National Institutes of Health, Department of Health and Human Services under Contract Nos. HHSN272201200025C and HHSN272200700057C. All data sets except for the Mtb Rv1496-GDP (3MD0) complex were obtained through the ALS Collaborative Crystallography program. The Berkeley Center for Structural Biology is supported in part by the National Institutes of Health, National Institute of General Medical Sciences, and the Howard Hughes Medical Institute. The Advanced Light Source is supported by the Director, Office of Science, Office of Basic Energy Sciences, and the U.S. Department of Energy under Contract No. DE-AC02-05CH11231.
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