Open AccessThe stable evolutionary fixation of a bifunctional tyrosine‐pathway protein in enteric bacteria
Author(s) -
Ahmad Suhail,
Jensen Roy A.
Publication year - 1988
Publication title -
fems microbiology letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.899
H-Index - 151
eISSN - 1574-6968
pISSN - 0378-1097
DOI - 10.1111/j.1574-6968.1988.tb02580.x
Subject(s) - bifunctional , chorismate mutase , biochemistry , phosphofructokinase 2 , biology , tyrosine , mutase , bacteria , biosynthesis , enzyme , genetics , catalysis
The bifunctional T‐protein (chorismate mutase‐T: cyclohexadienyl dehydrogenase) of l ‐tyrosine biosynthesis was found to be present in all genera making up the enteric bacteria. The dehydrogenase component of the T‐protein was active with both prephenate and l ‐arogenate, showing it to be a cyclohexadienyl dehydrogenase. The dehydrogenase component, but not the mutase component, of the T‐protein was feedback‐inhibited by l ‐tyrosine. Unlike some other bifunctional proteins, the T‐protein has evolved recently and is not ubiquitous. However, once the biochemical specialization of bifunctionality becomes established, the results indicate that such character states are strongly conserved through evolutionary time. Thus, bifunctional proteins can provide particularly reliable markers for small (recent origin), intermediate, and large (ancient origin) phylogenetic clusters.