1xa3

Crystal structure of CaiB, a type III CoA transferase in carnitine metabolism

spinqualitylabelsall models 1xa3, resolution 1.85Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 1xa3 is a 2 chain structure with sequence from Escherichia coli. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 1.85Å Ligands: BTB, MSE, SO4 Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function CAIB_ECOLI Catalyzes the reversible transfer of the CoA moiety from gamma-butyrobetainyl-CoA to L-carnitine to generate L-carnitinyl-CoA and gamma-butyrobetaine. Is also able to catalyze the reversible transfer of the CoA moiety from gamma-butyrobetainyl-CoA or L-carnitinyl-CoA to crotonobetaine to generate crotonobetainyl-CoA. Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMed Carnitine is an important molecule in human metabolism, mainly because of its role in the transport of long-chain fatty acids across the inner mitochondrial membrane. Escherichia coli uses carnitine as a terminal electron acceptor during anaerobic metabolism. Bacteria present in our large intestine break down carnitine that is not absorbed in the small intestine. One part of this catabolic pathway is reversible and can be utilized for bioproduction of large amounts of stereochemically pure L-carnitine, which is used medically for the treatment of a variety of human diseases. Here, we present the crystal structure of the E. coli protein CaiB, which is a member of the recently identified type-III coenzyme A (CoA) transferase family and catalyzes the transfer of the CoA moiety between gamma-butyrobetaine-CoA and carnitine forming carnityl-CoA and gamma-butyrobetaine. This is the first protein from the carnitine metabolic pathway to be structurally characterized. The structure of CaiB reveals a spectacular fold where two monomers are interlaced to form an interlocked dimer. A molecule of the crystallization buffer bis-(2-hydroxyethyl)imino-tris(hydroxymethyl)methane (bis-tris) is bound in a large pocket located primarily in the small domain, and we propose that this pocket constitutes the binding site for both substrate moieties participating in the CaiB transfer reaction. The binding of CoA to CaiB induces a domain movement that closes the active site of the protein. This is the first observation of a domain movement in the type-III CoA transferase family and can play an important role in coupling substrate binding to initiation of the catalytic reaction. Crystal structure of CaiB, a type-III CoA transferase in carnitine metabolism.,Stenmark P, Gurmu D, Nordlund P Biochemistry. 2004 Nov 9;43(44):13996-4003. PMID:15518548 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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