Journal:FEBS Open Bio:1: Difference between revisions
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''Mycobacterium tuberculosis'' <scene name='76/763765/Cv/2'>AccA3 adopts the ATPgrasp superfamily fold</scene>, and crystallized as a <scene name='76/763765/Cv/3'>dimer in the asymmetric unit</scene>. <scene name='76/763765/Cv/4'>The ordered structure of domain B is missing in chain B</scene>. | ''Mycobacterium tuberculosis'' <scene name='76/763765/Cv/2'>AccA3 adopts the ATPgrasp superfamily fold</scene>, and crystallized as a <scene name='76/763765/Cv/3'>dimer in the asymmetric unit</scene>. <scene name='76/763765/Cv/4'>The ordered structure of domain B is missing in chain B</scene>. | ||
Previous structures have shown defined ‘open’ and ‘closed’ states of the B-domain<ref>pmid 19213731</ref><ref>pmid 7915138</ref>. In addition, the biotin carboxylase domain of pyruvate carboxylase from ''Bacillus thermodenitrificans'' displays what appears to be an intermediate, but defined, conformation <ref>pmid 17642515</ref>. In the current structure, however, while <scene name='76/763765/Cv/6'>protomer A</scene> represents the previously observed ‘closed’ state, <scene name='76/763765/Cv/7'>protomer B</scene> represent a different structural state where no conformation is present in high enough occupancy to be possible to reliably model. MTb AccA3, subunit A (blue) and subunit B (yellow), unbound BDC from Escherichia coli (gray) (PDB [[1bnc]]). Based on the location of the segment of positive difference density relative to protomer B, it is, however, clear that the location of the B-domain in the partially occupied structural state that gives rise to this density is not the same as either the previously described ‘closed’ or ‘open’ states. Rather, the density suggests an even more extended conformation of the B-domain relative to the rest of the protein. Together, the most likely interpretation of the combined structural data of biotin-dependent carboxylases is that the B-domain is dynamic over a continuum of conformations, or several defined conformations. | Previous structures have shown defined ‘open’ and ‘closed’ states of the B-domain<ref>pmid 19213731</ref><ref>pmid 7915138</ref>. In addition, the biotin carboxylase domain of pyruvate carboxylase from ''Bacillus thermodenitrificans'' displays what appears to be an intermediate, but defined, conformation <ref>pmid 17642515</ref>. In the current structure, however, while <scene name='76/763765/Cv/6'>protomer A</scene> represents the previously observed ‘closed’ state, <scene name='76/763765/Cv/7'>protomer B</scene> represent a different structural state where no conformation is present in high enough occupancy to be possible to reliably model. MTb AccA3, subunit A (blue) and subunit B (yellow), unbound BDC from ''Escherichia coli'' (gray) (PDB [[1bnc]]). Based on the location of the segment of positive difference density relative to protomer B, it is, however, clear that the location of the B-domain in the partially occupied structural state that gives rise to this density is not the same as either the previously described ‘closed’ or ‘open’ states. Rather, the density suggests an even more extended conformation of the B-domain relative to the rest of the protein. Together, the most likely interpretation of the combined structural data of biotin-dependent carboxylases is that the B-domain is dynamic over a continuum of conformations, or several defined conformations. | ||
<scene name='76/763765/Cv/8'>Structural model</scene> of biotin and ADP binding in MTb AccA3 based on the biotin and ADP-bound ''Escherichia coli'' BDC (PDB [[3g8c]]). Substrate-bridging loop of ''MTb'' AccA3 rendered in pink and ''E. coli'' BDC in cyan. | <scene name='76/763765/Cv/8'>Structural model</scene> of biotin and ADP binding in MTb AccA3 based on the biotin and ADP-bound ''Escherichia coli'' BDC (PDB [[3g8c]]). Substrate-bridging loop of ''MTb'' AccA3 rendered in pink and ''E. coli'' BDC in cyan. | ||
This page complements a publication in scientific journals and is one of the Proteopedia's Interactive 3D Complement pages. For additional details please see I3DC.
