The loss of the hemoglobin H2S-binding function in annelids from sulfide-free habitats reveals molecular adaptation driven by Darwinian positive selection.

ABSTRACT: The hemoglobin of the deep-sea hydrothermal vent vestimentiferan Riftia pachyptila (annelid) is able to bind toxic hydrogen sulfide (H(2)S) to free cysteine residues and to transport it to fuel endosymbiotic sulfide-oxidising bacteria. The cysteine residues are conserved key amino acids in annelid globins living in sulfide-rich environments, but are absent in annelid globins from sulfide-free environments. Synonymous and nonsynonymous substitution analysis from two different sets of orthologous annelid globin genes from sulfide rich and sulfide free environments have been performed to understand how the sulfide-binding function of hemoglobin appeared and has been maintained during the course of evolution. This study reveals that the sites occupied by free-cysteine residues in annelids livi

SUBMITTER: Bailly X 

PROVIDER: S-EPMC156296 | biostudies-literature | 2003 May

REPOSITORIES: biostudies-literature