1FLP

STRUCTURE OF THE SULFIDE-REACTIVE HEMOGLOBIN FROM THE CLAM LUCINA PECTINATA: CRYSTALLOGRAPHIC ANALYSIS AT 1.5 ANGSTROMS RESOLUTION

1FLP の概要

• エントリーDOI: 10.2210/pdb1flp/pdb
• 分子名称: HEMOGLOBIN I (AQUO MET), PROTOPORPHYRIN IX CONTAINING FE (3 entities in total)
• 機能のキーワード: oxygen transport
• 由来する生物種: Lucina pectinata
• 細胞内の位置: Cytoplasm: P41260
• タンパク質・核酸の鎖数: 1
• 化学式量合計: 15375.93

構造登録者

Rizzi, M.,Wittenberg, J.B.,Ascenzi, P.,Fasano, M.,Coda, A.,Bolognesi, M. (登録日: 1994-05-16, 公開日: 1994-07-31, 最終更新日: 2024-02-07)

主引用文献

Rizzi, M.,Wittenberg, J.B.,Coda, A.,Fasano, M.,Ascenzi, P.,Bolognesi, M.
Structure of the sulfide-reactive hemoglobin from the clam Lucina pectinata. Crystallographic analysis at 1.5 A resolution.
J.Mol.Biol., 244:86-99, 1994

PubMed Abstract: The crystal structure of the aquo-met form of the sulfide-reactive hemoglobin (component I) from the gill of the symbiont-harboring mollusc, Lucina pectinata, has been solved and refined at 1.5 A resolution, based on synchrotron radiation X-ray diffraction data, and employing molecular replacement techniques. The crystallographic R-factor, calculated for the data in the 15.0 to 1.5 A resolution range, is 0.170, with highly regular stereochemical parameters for the protein model, and including 131 water molecules. The monomeric hemoglobin I chain consists of 142 amino acid residues, which have been partly identified on the basis of the crystallographic analysis. The molecule is characterized by an unusual distribution of aromatic residues, particularly in the region surrounding the distal site in the heme pocket. The heme distal residue is Gln(64)E7, while other notable amino acid substitutions include Trp(21)B2, Phe(29)B10, Leu(46)CD3, Phe(68)E11 and Trp(75)E18. An amino acid insertion (Ser44) is observed between sites CD1 and CD2. In the aquo-met protein, a water molecule is present at the sixth coordination position of the heme iron, and hydrogen bonded to Gln(64)E7. Simple model building shows that a dioxygen molecule, bound to ferrous protein, would contact with its free atom the ring edge of Phe(29)B10, being thus stabilized at the coordination site by an aromatic-electrostatic interaction. Similarly, the unique packing and organization of aromatic residues in the surroundings of the heme distal site is proposed as the molecular basis of the very high affinity of Lucina pectinata hemoglobin I for hydrogen sulfide, considered as one of the two physiological ligands of the protein.

PubMed: 7966324
DOI: 10.1006/jmbi.1994.1706

実験手法

X-RAY DIFFRACTION (1.5 Å)