1lsv
From Proteopedia
(New page: 200px<br /><applet load="1lsv" size="450" color="white" frame="true" align="right" spinBox="true" caption="1lsv, resolution 2.40Å" /> '''Crystal structure of...) |
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| - | [[Image:1lsv.gif|left|200px]]<br /><applet load="1lsv" size=" | + | [[Image:1lsv.gif|left|200px]]<br /><applet load="1lsv" size="350" color="white" frame="true" align="right" spinBox="true" |
caption="1lsv, resolution 2.40Å" /> | caption="1lsv, resolution 2.40Å" /> | ||
'''Crystal structure of the CO-bound BjFixL heme domain'''<br /> | '''Crystal structure of the CO-bound BjFixL heme domain'''<br /> | ||
==Overview== | ==Overview== | ||
| - | Structures of the Bradyrhizobium japonicum FixL heme domain have been | + | Structures of the Bradyrhizobium japonicum FixL heme domain have been determined in the absence and presence of specific ligands to elucidate the detailed features of its O2 sensing mechanism. The putative roles of spin-state and steric hindrance were evaluated by the structure determination of ferrous CO-bound BjFixLH and correlating its features with other ligand-bound structures. As found for NO-BjFixLH, no protein conformational change was observed in CO-BjFixLH, suggesting a more complicated mechanism than solely spin state or ligand sterics. To evaluate the role of oxidation state, the structure of the ferrous deoxy-BjFixLH was determined. The structure of deoxy-BjFixLH was found to be virtually identical to the structure of the ferric met-BjFixLH. The role of hydrogen bonding of substrates to a heme-pocket water was evaluated by determining the structure of BjFixLH bound to 1-methyl-imidazole that cannot form a hydrogen bond with this water. In this case, the heme-mediated conformational change was observed, limiting the potential importance of this interaction. Finally, the structure of cyanomet-BjFixLH was revisited to rule out concerns regarding the partial occupancy of the cyanide ligand in a previous structure. In the revised structure, Arg 220 was found to move into the heme pocket to form a hydrogen bond to the bound cyanide ligand. The implications of these results on FixL's sensing mechanism are discussed. |
==About this Structure== | ==About this Structure== | ||
| - | 1LSV is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Bradyrhizobium_japonicum Bradyrhizobium japonicum] with HEM and CMO as [http://en.wikipedia.org/wiki/ligands ligands]. Full crystallographic information is available from [http:// | + | 1LSV is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Bradyrhizobium_japonicum Bradyrhizobium japonicum] with <scene name='pdbligand=HEM:'>HEM</scene> and <scene name='pdbligand=CMO:'>CMO</scene> as [http://en.wikipedia.org/wiki/ligands ligands]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1LSV OCA]. |
==Reference== | ==Reference== | ||
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[[Category: Single protein]] | [[Category: Single protein]] | ||
[[Category: Arndt, J.]] | [[Category: Arndt, J.]] | ||
| - | [[Category: Chan, M | + | [[Category: Chan, M K.]] |
[[Category: Hao, B.]] | [[Category: Hao, B.]] | ||
[[Category: Isaza, C.]] | [[Category: Isaza, C.]] | ||
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[[Category: pas fold]] | [[Category: pas fold]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 13:48:06 2008'' |
Revision as of 11:48, 21 February 2008
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Crystal structure of the CO-bound BjFixL heme domain
Overview
Structures of the Bradyrhizobium japonicum FixL heme domain have been determined in the absence and presence of specific ligands to elucidate the detailed features of its O2 sensing mechanism. The putative roles of spin-state and steric hindrance were evaluated by the structure determination of ferrous CO-bound BjFixLH and correlating its features with other ligand-bound structures. As found for NO-BjFixLH, no protein conformational change was observed in CO-BjFixLH, suggesting a more complicated mechanism than solely spin state or ligand sterics. To evaluate the role of oxidation state, the structure of the ferrous deoxy-BjFixLH was determined. The structure of deoxy-BjFixLH was found to be virtually identical to the structure of the ferric met-BjFixLH. The role of hydrogen bonding of substrates to a heme-pocket water was evaluated by determining the structure of BjFixLH bound to 1-methyl-imidazole that cannot form a hydrogen bond with this water. In this case, the heme-mediated conformational change was observed, limiting the potential importance of this interaction. Finally, the structure of cyanomet-BjFixLH was revisited to rule out concerns regarding the partial occupancy of the cyanide ligand in a previous structure. In the revised structure, Arg 220 was found to move into the heme pocket to form a hydrogen bond to the bound cyanide ligand. The implications of these results on FixL's sensing mechanism are discussed.
About this Structure
1LSV is a Single protein structure of sequence from Bradyrhizobium japonicum with and as ligands. Full crystallographic information is available from OCA.
Reference
Structure-based mechanism of O2 sensing and ligand discrimination by the FixL heme domain of Bradyrhizobium japonicum., Hao B, Isaza C, Arndt J, Soltis M, Chan MK, Biochemistry. 2002 Oct 29;41(43):12952-8. PMID:12390021
Page seeded by OCA on Thu Feb 21 13:48:06 2008
Categories: Bradyrhizobium japonicum | Single protein | Arndt, J. | Chan, M K. | Hao, B. | Isaza, C. | Soltis, M. | CMO | HEM | Pas fold
