2ig3: Difference between revisions

Revision as of 07:27, 4 May 2008

Crystal structure of group III truncated hemoglobin from Campylobacter jejuni

OverviewOverview

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 StructureAbout this Structure

2IG3 is a Single protein structure of sequence from Campylobacter jejuni. Full crystallographic information is available from OCA.

ReferenceReference

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 Sun May 4 07:27:51 2008

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OCA

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 [[Image:2ig3.gif|left|200px]]
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-|GENE= ctb ([http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&srchmode=5&id=197 Campylobacter jejuni])
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-}}
 '''Crystal structure of group III truncated hemoglobin from Campylobacter jejuni'''
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 [[Category: Pesce, A.]]
 [[Category: 2-on-2 globin]]
-[[Category: truncated hemoglobin]]
+[[Category: Truncated hemoglobin]]
+''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sun May  4 07:27:51 2008''
-''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Mon Mar 31 03:43:56 2008''