Abstract
Flavohaemoglobins were first described in yeast as early as the 1970s but their functions were unclear. The surge in interest in nitric oxide biology and both serendipitous and hypothesis-driven discoveries in bacterial systems have transformed our understanding of this unusual two-domain globin into a comprehensive, yet undoubtedly incomplete, appreciation of its pre-eminent role in nitric oxide detoxification. Here, I focus on research on the flavohaemoglobins of microorganisms, especially of bacteria, and update several earlier and more comprehensive reviews, emphasising advances over the past 5 to 10 years and some controversies that have arisen. Inevitably, in light of space restrictions, details of nitric oxide metabolism and globins in higher organisms are brief.
Highlights
Flavohaemoglobins were first described in yeast as early as the 1970s but their functions were unclear
Nitrosonium cation (NO+), nitroxyl anion (NO−, HNO is dominant at pH 7), nitrogen dioxide (NO2), and dinitrogen trioxide (N2O3, the product of nitric oxide (NO) reacting with O2) and peroxynitrite (ONOO−, the product of NO reacting with superoxide radical) are not “forms of NO” but products of NO reactions
The complex biology, chemistry and medical significance of NOS are outside the scope of this commentary, but excellent reviews and articles cover mammalian[9], microbial[10] and the elusive plant NOS-like[11] activities
Summary
The flavohaemoglobins of numerous bacterial species and groups, yeasts, fungi and protozoa continue to fascinate those devoted to understanding globin functions, NO homeostasis in biology and clinical medicine. It is striking, though, that throughout this period (almost 30 years), no clear evidence has emerged for a flavohaemoglobin in higher organisms. Though, that throughout this period (almost 30 years), no clear evidence has emerged for a flavohaemoglobin in higher organisms This continues to offer the hope that such a protein, a “single protein metabolic module”, might represent a useful target for antimicrobial therapies. Imidazoles with great efficacy have been identified as inhibitors and these efforts, in concert with increasing understanding of protein function, ligand and electron migration within such flavoproteins, may yet give us new antimicrobial weapons
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
