2MGJ

HIGH RESOLUTION CRYSTAL STRUCTURES OF FIVE DISTAL HISTIDINE MUTANTS OF SPERM WHALE MYOGLOBIN

DOI: 10.2210/pdb2MGJ/pdb

Classification: OXYGEN STORAGE
Organism(s): Physeter catodon
Mutation(s): No

Deposited: 1993-05-10 Released: 1994-01-31
Deposition Author(s): Quillin, M.L., Arduini, R.M., Phillips Jr., G.N.

Experimental Data Snapshot

Method: X-RAY DIFFRACTION
Resolution: 2.00 Å
R-Value Work: 0.156
R-Value Observed: 0.156

wwPDB Validation 3D Report Full Report

This is version 1.2 of the entry. See complete history.

Literature

High-resolution crystal structures of distal histidine mutants of sperm whale myoglobin.

Quillin, M.L., Arduini, R.M., Olson, J.S., Phillips Jr., G.N.

(1993) J Mol Biol 234: 140-155

PubMed: 8230194 Search on PubMed
DOI: 10.1006/jmbi.1993.1569
Primary Citation of Related Structures:
1MOD, 1MOC, 1MOB, 2MGC, 2MGB, 2MGA, 2MGK, 2MGJ, 2MGI, 2MGH

PubMed Abstract:

The highly conserved distal histidine residue (His64) of sperm whale myoglobin modulates the affinity of ligands. In an effort to fully characterize the effects of mutating residue 64, we have determined the high-resolution crystal structures of the Gly64, Val64, Leu64, Thr64 and Gln64 mutants in several liganded forms. Metmyoglobins with hydrophobic substitutions at residue 64 (Val64 and Leu64) lack a water molecule at the sixth coordination position, while those with polar amino acid residues at this position (wild-type and Gln64) retain a covalently bound water molecule. In the Thr64 mutant, the bound water position is only partially occupied. In contrast, mutating the distal histidine residue to glycine does not cause loss of the coordinated water molecule, because the hydrogen bond from the imidazole side-chain is replaced by one from a well-ordered solvent water molecule. Differences in water structure around the distal pocket are apparent also in the structures of deoxymyoglobin mutants. The water molecule that is hydrogen-bonded to the N epsilon atom of histidine 64 in wild-type deoxymyoglobin is not found in any of the position 64 mutant structures that were determined. Comparison of the carbonmonoxy structures of wild-type, Gly64, Leu64 and Gln64 myoglobins in the P6 crystal form shows that the conformation of the Fe-C-O complex is nearly linear and is independent of the identity of the amino acid residue at position 64. However, the effect of CO binding on the conformation of residue 64 is striking. Superposition of deoxy and carbonmonoxy structures reveals significant displacements of the residue 64 side-chain in the wild-type and Gln64 myoglobins, but no displacement in the Leu64 mutant. These detailed structural studies provide key insights into the mechanisms of ligand binding and discrimination in myoglobin.

Related Citations:

Crystal Structure of Myoglobin from a Synthetic Gene
Phillips Jr., G.N., Arduini, R.M., Springer, B.A., Sligar, S.G.
(1990) Proteins 7: 358

High-Level Expression of Sperm Whale Myoglobin in Escherichia Coli
Springer, B.A., Sligar, S.G.
(1987) Proc Natl Acad Sci U S A 84: 8961

Organizational Affiliation:

Department of Biochemistry and Cell Biology, Rice University, Houston, TX 77251.

Macromolecules

Find similar proteins by:

(by identity cutoff) | Structure

Entity ID: 1
Molecule	Chains	Sequence Length	Organism	Details	Image
MYOGLOBIN	A	154	Physeter catodon	Mutation(s): 0 Gene Names: SYNTHETIC GENE, MB
Find proteins for P02185 (Physeter macrocephalus) Explore P02185 Go to UniProtKB: P02185
Protein Feature View Expand
Reference Sequence

Small Molecules

Ligands 2 Unique
ID	Chains	Name / Formula / InChI Key	2D Diagram	3D Interactions
HEM Query on HEM Download Ideal Coordinates CCD File SDF format, chain C [A] MOL2 format, chain C [A]	A	PROTOPORPHYRIN IX CONTAINING FE C₃₄ H₃₂ Fe N₄ O₄ KABFMIBPWCXCRK-RGGAHWMASA-L		Ligand Interaction
SO4 Query on SO4 Download Ideal Coordinates CCD File SDF format, chain B [A] MOL2 format, chain B [A]	A	SULFATE ION O₄ S QAOWNCQODCNURD-UHFFFAOYSA-L		Ligand Interaction