PDBsum entry 4pqb

Oxygen transport

PDB id: 4pqb

Contents

Protein chain

153 a.a.

Ligands

HEM

Waters ×148

PDB id:

4pqb

Name:

Oxygen transport

Title:

A sperm whale myoglobin double mutant l29e/f43h mb with a non-native bis-his (his64/his93) coordination

Structure:

Myoglobin. Chain: a. Fragment: whale sperm mutant. Engineered: yes. Mutation: yes

Source:

Physeter catodon. Sperm whale. Organism_taxid: 9755. Gene: mb. Expressed in: escherichia coli. Expression_system_taxid: 562

Resolution:

1.94Å R-factor: 0.186 R-free: 0.219

Authors:

L.Ying-Wu,T.Xiang-Shi,L.Wei

Key ref:

J.F.Du et al. (2015). Regulating the coordination state of a heme protein by a designed distal hydrogen-bonding network. Chemistryopen, 4, 97. PubMed id: 25969804 DOI: 10.1002/open.201402108

Date:

01-Mar-14 Release date: 14-Jan-15

Protein chain

P02185  (MYG_PHYMC) -  Myoglobin from Physeter macrocephalus

Seq: 154 a.a.

Struc: 153 a.a.*

* PDB and UniProt seqs differ at 2 residue positions (black crosses)

DOI no: 10.1002/open.201402108

Chemistryopen 4:97 (2015)

PubMed id: 25969804

Regulating the coordination state of a heme protein by a designed distal hydrogen-bonding network.

J.F.Du, W.Li, L.Li, G.B.Wen, Y.W.Lin, X.Tan.

ABSTRACT

Heme coordination state determines the functional diversity of heme proteins. Using myoglobin as a model protein, we designed a distal hydrogen-bonding network by introducing both distal glutamic acid (Glu29) and histidine (His43) residues and regulated the heme into a bis-His coordination state with native ligands His64 and His93. This resembles the heme site in natural bis-His coordinated heme proteins such as cytoglobin and neuroglobin. A single mutation of L29E or F43H was found to form a distinct hydrogen-bonding network involving distal water molecules, instead of the bis-His heme coordination, which highlights the importance of the combination of multiple hydrogen-bonding interactions to regulate the heme coordination state. Kinetic studies further revealed that direct coordination of distal His64 to the heme iron negatively regulates fluoride binding and hydrogen peroxide activation by competing with the exogenous ligands. The new approach developed in this study can be generally applicable for fine-tuning the structure and function of heme proteins.