CRYSTAL STRUCTURE OF ASIAN ELEPHANT (ELEPHAS MAXIMUS) CYANO-MET MYOGLOBIN AT 1.78 ANGSTROMS RESOLUTION. PHE 29 (B10) ACCOUNTS FOR ITS UNUSUAL LIGAND BINDING PROPERTIES
Crystal structure of Asian elephant (Elephas maximus) cyano-metmyoglobin at 1.78-A resolution. Phe29(B10) accounts for its unusual ligand binding properties.
The crystal structure of Asian elephant cyano-metmyoglobin which has a glutamine instead of the usual distal site histidine has been determined to high resolution. In addition to this replacement, the substitution of a conserved leucine residue in po ...
The crystal structure of Asian elephant cyano-metmyoglobin which has a glutamine instead of the usual distal site histidine has been determined to high resolution. In addition to this replacement, the substitution of a conserved leucine residue in position 29(B10) at the distal side by a phenylalanine was unambiguously identified based on the available electron density. The suspicion, that there were errors in the original sequence which has caused some confusion, is thus confirmed. Comparison with other myoglobin structures in various ligated forms reveals an essentially unchanged tertiary structure in elephant myoglobin despite the two amino acid substitutions in the heme pocket. Our current structural model shows that the N epsilon 2 atom of Gln64(E7) has moved with respect to the corresponding nitrogen position of His64(E7) in the CO complex of sperm whale myoglobin. The newly assigned residue Phe29(B10) penetrates into the distal side of the heme pocket approaching the ligand within van der Waals distance and causing a much more crowded heme pocket compared to other myoglobins. Kinetic properties of Asian elephant myoglobin, wild type, and recombinant sperm whale myoglobins are discussed in relation to the structural consequences of the two amino acid substitutions H64Q and L29F.
Related Citations:
1H NMR Investigation of the Heme Cavity of Elephant (E7 Gln) met-Cyano-Myoglobin. Evidence for a B-Helix Phenylalanine Interaction with Bound Ligand Vyas, K.,Rajarathnam, K.,Yu, L.P.,Emerson, S.D.,La Mar, G.N.,Krishnamoorthi, R. (1993) J.Biol.Chem. 268: 14826
A Double Mutant of Sperm Whale Myoglobin Mimics the Structure and Function of Elephant Myoglobin Zhao, X.,Vyas, K.,Nguyen, B.D.,Rajarathnam, K.,La Mar, G.N.,Li, T.,Phillips Jr., G.N.,Eich, R.F.,Olson, J.S.,Ling, J.,Bocian, D.F. () TO BE PUBLISHED --: --
Organizational Affiliation:
Laboratory of Biochemistry I, Swiss Federal Institute of Technology, CH-8092 Zürich.
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