Haemoglobins of Mycobacteria: structural features and biological functions.
The genus Mycobacterium is comprised of Gram-positive bacteria occupying a wide range of natural habitats and includes species that range from severe intracellular pathogens to economically useful and harmless microbes. The recent upsurge in the availability of microbial genome data has shown that genes encoding haemoglobin-like proteins are ubiquitous among Mycobacteria and that multiple haemoglobins (Hbs) of different classes may be present in pathogenic and non-pathogenic species. The occurrence of truncated haemoglobins (trHbs) and flavohaemoglobins (flavoHbs) showing distinct haem active site structures and ligand-binding properties suggests that these Hbs may be playing diverse functions in the cellular metabolism of Mycobacteria. TrHbs and flavoHbs from some of the severe human pathogens such as Mycobacterium tuberculosis and Mycobacterium leprae have been studied recently and their roles in effective detoxification of reactive nitrogen and oxygen species, electron cycling, modulation of redox state of the cell and facilitation of aerobic respiration have been proposed. This multiplicity in the function of Hbs may aid these pathogens to cope with various environmental stresses and survive during their intracellular regime. This chapter provides recent updates on genomic, structural and functional aspects of Mycobacterial Hbs to address their role in Mycobacteria.
School of Life Sciences, Centre for Biomolecular Sciences, University of Nottingham, University Park, Nottingham, United Kingdom. Electronic address: kelly.davidge@nottingham.ac.uk.
Kelly S
KS
Davidge
Kanak L
KL
Dikshit
D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D001711:Biotransformation; D006420:Hemeproteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D053858:Metabolic Networks and Pathways; D008958:Models, Molecular; D009161:Mycobacterium / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D009569:Nitric Oxide / Q000378:metabolism / Q000633:toxicity; D010084:Oxidation-Reduction; D010100:Oxygen / Q000378:metabolism / Q000633:toxicity; D011487:Protein Conformation; D026361:Reactive Nitrogen Species / Q000378:metabolism / Q000633:toxicity; D017382:Reactive Oxygen Species / Q000378:metabolism / Q000633:toxicity; D054793:Truncated Hemoglobins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*
D001426:Bacterial Proteins; D006420:Hemeproteins; D026361:Reactive Nitrogen Species; D017382:Reactive Oxygen Species; D054793:Truncated Hemoglobins; C086193:flavohemoprotein, Bacteria; D009569:Nitric Oxide; D010100:Oxygen
Flavohaemoglobins; Mycobacterium; Nitric oxide scavenging; Oxidative stress; Oxygen binding; Redox reactions; Truncated haemoglobins