2ig3
From Proteopedia
(New page: 200px<br /> <applet load="2ig3" size="450" color="white" frame="true" align="right" spinBox="true" caption="2ig3, resolution 2.15Å" /> '''Crystal structure o...) |
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| - | [[Image:2ig3.gif|left|200px]]<br /> | + | [[Image:2ig3.gif|left|200px]]<br /><applet load="2ig3" size="350" color="white" frame="true" align="right" spinBox="true" |
| - | <applet load="2ig3" size=" | + | |
caption="2ig3, resolution 2.15Å" /> | caption="2ig3, resolution 2.15Å" /> | ||
'''Crystal structure of group III truncated hemoglobin from Campylobacter jejuni'''<br /> | '''Crystal structure of group III truncated hemoglobin from Campylobacter jejuni'''<br /> | ||
==Overview== | ==Overview== | ||
| - | Truncated hemoglobins (trHbs) constitute a distinct lineage in the globin | + | Truncated hemoglobins (trHbs) constitute a distinct lineage in the globin superfamily, distantly related in size and fold to myoglobin and monomeric hemoglobins. Their phylogenetic analyses revealed that three groups (I, II, and III) compose the trHb family. Group I and II trHbs adopt a simplified globin fold, essentially composed of a 2-on-2 alpha-helical sandwich, wrapped around the heme group. So far no structural data have been reported for group III trHbs. Here we report the three-dimensional structure of the group III trHbP from the eubacterium Campylobacter jejuni. The 2.15-A resolution crystal structure of C. jejuni trHbP (cyano-met form) shows that the 2-on-2 trHb fold is substantially conserved in the trHb group III, despite the absence of the Gly-based sequence motifs that were considered necessary for the attainment of the trHb specific fold. The heme crevice presents important structural modifications in the C-E region and in the FG helical hinge, with novel surface clefts at the proximal heme site. Contrary to what has been observed for group I and II trHbs, no protein matrix tunnel/cavity system is evident in C. jejuni trHbP. A gating movement of His(E7) side chain (found in two alternate conformations in the crystal structure) may be instrumental for ligand entry to the heme distal site. Sequence conservation allows extrapolating part of the structural results here reported to the whole trHb group III. |
==About this Structure== | ==About this Structure== | ||
| - | 2IG3 is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Campylobacter_jejuni Campylobacter jejuni] with CYN, ACT, SO4 and HEM as [http://en.wikipedia.org/wiki/ligands ligands]. Full crystallographic information is available from [http:// | + | 2IG3 is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Campylobacter_jejuni Campylobacter jejuni] with <scene name='pdbligand=CYN:'>CYN</scene>, <scene name='pdbligand=ACT:'>ACT</scene>, <scene name='pdbligand=SO4:'>SO4</scene> and <scene name='pdbligand=HEM:'>HEM</scene> as [http://en.wikipedia.org/wiki/ligands ligands]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=2IG3 OCA]. |
==Reference== | ==Reference== | ||
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[[Category: truncated hemoglobin]] | [[Category: truncated hemoglobin]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 17:52:18 2008'' |
Revision as of 15:52, 21 February 2008
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Crystal structure of group III truncated hemoglobin from Campylobacter jejuni
Overview
Truncated hemoglobins (trHbs) constitute a distinct lineage in the globin superfamily, distantly related in size and fold to myoglobin and monomeric hemoglobins. Their phylogenetic analyses revealed that three groups (I, II, and III) compose the trHb family. Group I and II trHbs adopt a simplified globin fold, essentially composed of a 2-on-2 alpha-helical sandwich, wrapped around the heme group. So far no structural data have been reported for group III trHbs. Here we report the three-dimensional structure of the group III trHbP from the eubacterium Campylobacter jejuni. The 2.15-A resolution crystal structure of C. jejuni trHbP (cyano-met form) shows that the 2-on-2 trHb fold is substantially conserved in the trHb group III, despite the absence of the Gly-based sequence motifs that were considered necessary for the attainment of the trHb specific fold. The heme crevice presents important structural modifications in the C-E region and in the FG helical hinge, with novel surface clefts at the proximal heme site. Contrary to what has been observed for group I and II trHbs, no protein matrix tunnel/cavity system is evident in C. jejuni trHbP. A gating movement of His(E7) side chain (found in two alternate conformations in the crystal structure) may be instrumental for ligand entry to the heme distal site. Sequence conservation allows extrapolating part of the structural results here reported to the whole trHb group III.
About this Structure
2IG3 is a Single protein structure of sequence from Campylobacter jejuni with , , and as ligands. Full crystallographic information is available from OCA.
Reference
Structural determinants in the group III truncated hemoglobin from Campylobacter jejuni., Nardini M, Pesce A, Labarre M, Richard C, Bolli A, Ascenzi P, Guertin M, Bolognesi M, J Biol Chem. 2006 Dec 8;281(49):37803-12. Epub 2006 Oct 5. PMID:17023416
Page seeded by OCA on Thu Feb 21 17:52:18 2008
Categories: Campylobacter jejuni | Single protein | Ascenzi, P. | Bolognesi, M. | Guertin, M. | Labarre, M. | Nardini, M. | Pesce, A. | ACT | CYN | HEM | SO4 | 2-on-2 globin | Truncated hemoglobin
