Truncated hemoglobin o of Mycobacterium tuberculosis: the oligomeric state change and the interaction with membrane components.

Abstract

Being an obligate aerobe, the Mycobacterium tuberculosis cells would have to evolve a mechanism to collect and deliver the hardly available O(2) to survive in granulomas and to maintain the low level of respiration during latency. The M. tuberculosis truncated hemoglobin o (trHbO), when heterologously expressed in Escherichia coli cells, was found to significantly enhance the cellular respiration and cell growth. This study was undertaken in an attempt to understand the molecular details for trHbO to promote the cellular respiration, focusing on the ways through which trHbO is recruited to the cell membrane and O(2) molecules are delivered. Our data demonstrate that the trHbO protein is able to promote the growth of E. coli cells in a fashion that depends on the presence of the respiratory chain terminal oxidase cytochrome o complex (or Cyo complex). The trHbO protein appears to interact with the Cyo B subunit of the Cyo complex directly, likely in a dynamic manner. The trHbO is also able to bind membrane lipids in a non-specific way, during the process electrostatic and hydrophobic interactions both likely exist. Besides, binding with membrane induces the dissociation of trHbO from dimers to monomers. In light of these observations, a hypothesis was made to explain how trHbO might serve as an O(2) collector and/or reservoir for M. tuberculosis cells under O(2)-limiting or lacking conditions.

• Authors: Chong Liu, Yuan He, Zengyi Chang
• Journal: Biochemical and biophysical research communications (Biochem Biophys Res Commun) Vol. 316 Issue 4 Pg. 1163-72 (Apr 16 2004) ISSN: 0006-291X [Print] United States
• PMID: 15044107 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Bacterial Proteins
• Hemoglobins
• Membrane Lipids
• Polymers
• Recombinant Proteins
• Truncated Hemoglobins
• hemoglobin O, Mycobacterium tuberculosis
• Cytochromes b
• cytochrome o oxidase
• Electron Transport Complex IV

Topics

• Bacterial Proteins
• Cell Division (physiology)
• Cell Membrane (metabolism)
• Cell Respiration (physiology)
• Cytochromes b (metabolism)
• Dimerization
• Electron Transport Complex IV (metabolism)
• Escherichia coli (cytology, physiology)
• Hemoglobins (genetics, metabolism)
• Membrane Lipids (metabolism)
• Polymers (metabolism)
• Recombinant Proteins (metabolism)
• Truncated Hemoglobins