1MOH

FERRIC MONOMERIC HEMOGLOBIN I (HB I)

Summary for 1MOH

• Entry DOI: 10.2210/pdb1moh/pdb
• Descriptor: MONOMERIC HEMOGLOBIN I, PROTOPORPHYRIN IX CONTAINING FE, HYDROSULFURIC ACID, ... (4 entities in total)
• Functional Keywords: monomeric, hemoglobin (ferric), sulfide transport, oxygen transport
• Biological source: Lucina pectinata
• Cellular location: Cytoplasm: P41260
• Total number of polymer chains: 1
• Total formula weight: 15410.01

Authors

Rizzi, M.,Wittenberg, J.B.,Ascenzi, P.,Bolognesi, M. (deposition date: 1996-02-27, release date: 1996-08-01, Last modification date: 2024-02-14)

Primary citation

Rizzi, M.,Wittenberg, J.B.,Coda, A.,Ascenzi, P.,Bolognesi, M.
Structural bases for sulfide recognition in Lucina pectinata hemoglobin I.
J.Mol.Biol., 258:1-5, 1996

PubMed Abstract: The X-ray crystal structure of the sulfide derivative of ferric Lucina pectinata hemoglobin component I (HbI) has been determined at 1.9 A resolution (R-factor 0.186). The heme pocket structural organization of HbI is in keeping with its ligand binding properties. The fast sulfide association rate constant can be related to the presence of Gln(64)E7, as the heme distal residue, together with the protein structural properties in the CD-E distal region. Moreover, the very high sulfide affinity for HbI is reflected by the exceptionally slow ligand dissociation rate. The stabilization of the heme-bound sulfide molecule is achieved through hydrogen bonding to Gln(64)E7, as well as by finely tuned aromatic-electrostatic interactions with the clustered residues Phe(29)B10, Phe(43)CD1 and Phe(68)E11. Such a peculiar arrangement of phenylalanyl residues at the distal ligand binding site has not been observed before in the globin family, and is unique to HbI, a protein functionally devoted to sulfide transport.

PubMed: 8613980
DOI: 10.1006/jmbi.1996.0228

Experimental method

X-RAY DIFFRACTION (1.9 Å)