Skip to main content
OSTI.GOVU.S. Department of Energy Office of Scientific and Technical Information
U.S. Department of Energy
Office of Scientific and Technical Information
 

Structure of metallochaperone in complex with the cobalamin-binding domain of its target mutase provides insight into cofactor delivery

Journal Article · · Proceedings of the National Academy of Sciences of the United States of America
 [1];  [2];  [1]
  1. Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States)
  2. Harvard Univ., Cambridge, MA (United States); Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States)
+ Show Author Affiliations
G-protein metallochaperone MeaB in bacteria [methylmalonic aciduria type A (MMAA) in humans] is responsible for facilitating the delivery of adenosylcobalamin (AdoCbl) to methylmalonyl-CoA mutase (MCM), the only AdoCbl-dependent enzyme in humans. Genetic defects in the switch III region of MMAA lead to the genetic disorder methylmalonic aciduria in which the body is unable to process certain lipids. Here, we present a crystal structure of Methylobacterium extorquens MeaB bound to a nonhydrolyzable guanosine triphosphate (GTP) analog guanosine-5'-[(β,γ)-methyleno]triphosphate (GMPPCP) with the Cbl-binding domain of its target mutase enzyme (MeMCMcbl). This structure provides an explanation for the stimulation of the GTP hydrolyase activity of MeaB afforded by target protein binding. We find that upon MCMcbl association, one protomer of the MeaB dimer rotates ~180°, such that the inactive state of MeaB is converted to an active state in which the nucleotide substrate is now surrounded by catalytic residues. Importantly, it is the switch III region that undergoes the largest change, rearranging to make direct contacts with the terminal phosphate of GMPPCP. These structural data additionally provide insights into the molecular basis by which this metallochaperone contributes to AdoCbl delivery without directly binding the cofactor. Our data suggest a model in which GTP-bound MeaB stabilizes a conformation of MCM that is open for AdoCbl insertion, and GTP hydrolysis, as signaled by switch III residues, allows MCM to close and trap its cofactor. Substitutions of switch III residues destabilize the active state of MeaB through loss of protein:nucleotide and protein:protein interactions at the dimer interface, thus uncoupling GTP hydrolysis from AdoCbl delivery.
Research Organization:
Argonne National Laboratory (ANL), Argonne, IL (United States). Advanced Photon Source (APS)
Sponsoring Organization:
USDOE Office of Science (SC), Basic Energy Sciences (BES). Scientific User Facilities (SUF)
Grant/Contract Number:
AC02-06CH11357
OSTI ID:
2423657
Journal Information:
Proceedings of the National Academy of Sciences of the United States of America, Journal Name: Proceedings of the National Academy of Sciences of the United States of America Journal Issue: 8 Vol. 120; ISSN 0027-8424
Publisher:
National Academy of SciencesCopyright Statement
Country of Publication:
United States
Language:
English

References (43)

Classification and evolution of P-loop GTPases and related ATPases journal March 2002
A rapid and sensitive method for the quantitation of microgram quantities of protein utilizing the principle of protein-dye binding journal May 1976
How coenzyme B12 radicals are generated: the crystal structure of methylmalonyl-coenzyme A mutase at 2 å resolution journal March 1996
Conformational changes on substrate binding to methylmalonyl CoA mutase and new insights into the free radical mechanism journal June 1998
Metallochaperones journal June 2002
Protection and reactivation of human methylmalonyl-CoA mutase by MMAA protein journal January 2011
Human MMAA induces the release of inactive cofactor and restores methylmalonyl-CoA mutase activity through their complex formation journal November 2017
The tinker, tailor, soldier in intracellular B12 trafficking journal October 2009
Adenosyltransferase: an enzyme and an escort for coenzyme B12? journal June 2005
High resolution melting analysis of the MMAA gene in patients with cblA and in those with undiagnosed methylmalonic aciduria journal November 2012
Crystal Structure of Substrate Complexes of Methylmalonyl-CoA Mutase journal June 1999
Radical Carbon Skeleton Rearrangements:  Catalysis by Coenzyme B 12 -Dependent Mutases journal June 2003
A switch III motif relays signaling between a B12 enzyme and its G-protein chaperone journal July 2013
Adenosyltransferase tailors and delivers coenzyme B12 journal February 2008
Enzymatic assembly of DNA molecules up to several hundred kilobases journal April 2009
Metallochaperones and metalloregulation in bacteria journal May 2017
Visualization of a radical B 12 enzyme with its G-protein chaperone journal February 2015
Structures of the Human GTPase MMAA and Vitamin B 12 -dependent Methylmalonyl-CoA Mutase and Insight into Their Complex Formation journal September 2010
Novel Coenzyme B 12 -dependent Interconversion of Isovaleryl-CoA and Pivalyl-CoA journal December 2011
Autoinhibition and Signaling by the Switch II Motif in the G-protein Chaperone of a Radical B 12 Enzyme journal August 2013
Switch I-dependent allosteric signaling in a G-protein chaperone–B12 enzyme complex journal October 2017
MeaB Is a Component of the Methylmalonyl-CoA Mutase Complex Required for Protection of the Enzyme from Inactivation journal January 2004
Energetics of Interaction between the G-protein Chaperone, MeaB, and B 12 -dependent Methylmalonyl-CoA Mutase journal April 2006
Structural Insights into HypB, a GTP-binding Protein That Regulates Metal Binding journal June 2006
Crystal Structure and Mutagenesis of the Metallochaperone MeaB journal August 2007
Metallochaperones, an Intracellular Shuttle Service for Metal Ions journal May 2000
Navigating the B 12 Road: Assimilation, Delivery, and Disorders of Cobalamin journal March 2013
The role of nucleoside triphosphate hydrolase metallochaperones in making metalloenzymes journal April 2022
Phaser crystallographic software journal July 2007
Integration, scaling, space-group assignment and post-refinement journal January 2010
PHENIX: a comprehensive Python-based system for macromolecular structure solution journal January 2010
Features and development of Coot journal March 2010
Overview of the CCP 4 suite and current developments journal March 2011
Improvement of molecular-replacement models with Sculptor journal March 2011
The Guanine Nucleotide-Binding Switch in Three Dimensions journal November 2001
Klebsiella aerogenes urease gene cluster: sequence of ureD and demonstration that four accessory genes (ureD, ureE, ureF, and ureG) are involved in nickel metallocenter biosynthesis. journal July 1992
The product of the hypB gene, which is required for nickel incorporation into hydrogenases, is a novel guanine nucleotide-binding protein. journal February 1993
Structure-Function Relationships of the G Domain, a Canonical Switch Motif journal July 2011
Radical Use of Rossmann and TIM Barrel Architectures for Controlling Coenzyme B 12 Chemistry journal June 2012
G PROTEIN MECHANISMS:Insights from Structural Analysis journal June 1997
Structure of UreG/UreF/UreH Complex Reveals How Urease Accessory Proteins Facilitate Maturation of Helicobacter pylori Urease journal October 2013
Common mechanisms of catalysis in small and heterotrimeric GTPases and their respective GAPs journal May 2017
Collaboration gets the most out of software journal September 2013

Similar Records

Crystal Structure And Mutagenisis of the Metallochaperone MeaB: Insight Into the Causes of the Methylmalonic Aciduria
Journal Article · Mon Jun 01 00:00:00 EDT 2009 · J. Biol. Chem. 282:31308,2007 · OSTI ID:953995
Architecture of the human G-protein-methylmalonyl-CoA mutase nanoassembly for B12 delivery and repair
Journal Article · Tue Jul 18 20:00:00 EDT 2023 · Nature Communications · OSTI ID:2423293
Visualization of a radical B12 enzyme with its G-protein chaperone
Journal Article · Sun Feb 08 19:00:00 EST 2015 · Proceedings of the National Academy of Sciences of the United States of America · OSTI ID:1171849

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
G-protein chaperone
cobalamin
cofactor delivery
metalloenzyme maturation
signal transduction