4nk1 | pdb_00004nk1

Crystal structure of phosphate-bound Hell's gate globin IV

spinqualitylabelsall models 4nk1, resolution 2.21Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 4nk1 is a 2 chain structure with sequence from Methylacidiphilum infernorum V4. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 2.21Å Ligands: HEM, PO4 Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function B3DVC3_METI4 Publication Abstract from PubMed A truncated haemoglobin (tHb) has been identified in an acidophilic and thermophilic methanotroph Methylacidiphilium infernorum. Hell's Gate Globin IV (HGbIV) and its related tHbs differ from all other bacterial tHbs due to their distinctively large sequence and polar distal haem pocket residues. Here we report the crystal structure of HGbIV determined at 1.96 A resolution. The HGbIV structure has the distinctive 2/2 alpha-helical structure with extensions at both termini. It has a large distal site cavity in the haem pocket surrounded by four polar residues: His70(B9), His71(B10), Ser97(E11) and Trp137(G8). This cavity can bind bulky ligands such as a phosphate ion. Conformational shifts of His71(B10), Leu90(E4) and Leu93(E7) can also provide more space to accommodate larger ligands than the phosphate ion. The entrance/exit of such bulky ligands might be facilitated by positional flexibility in the CD1 loop, E helix and haem-propionate A. Therefore, the large cavity in HGbIV with polar His70(B9) and His71(B10), in contrast to the distal sites of other bacterial tHbs surrounded by non-polar residues, suggests its distinct physiological functions. Crystal structure of truncated haemoglobin from an extremely thermophilic and acidophilic bacterium.,Jamil F, Teh AH, Schadich E, Saito JA, Najimudin N, Alam M J Biochem. 2014 Aug;156(2):97-106. doi: 10.1093/jb/mvu023. Epub 2014 Apr 14. PMID:24733432 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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