This enzyme, found in bacteria and plants, acts on three different substrates. It is involved in the S-adenosyl-L-methionine (SAM, AdoMet) cycle, which recycles S-adenosyl-L-homocysteine back to SAM, and in salvage pathways for 5'-deoxyadenosine and S-methyl-5'-thioadenosine, which are produced from SAM during the action of many enzymes. cf. the plant enzyme EC 3.2.2.16, methylthioadenosine nucleosidase.
History
EC 3.2.2.9 created 1972, modified 2004, modified 2020
Characterization of recombinant Eschericha coli 5'-methylthioadenosine/S-adenosylhomocysteine nucleosidase: analysis of enzymatic activity and substrate specificity.
North JA, Wildenthal JA, Erb TJ, Evans BS, Byerly KM, Gerlt JA, Tabita FR
Title
A bifunctional salvage pathway for two distinct S-adenosylmethionine by-products that is widespread in bacteria, including pathogenic Escherichia coli.
The enzyme, found in several bacterial species, catalyses a step in a modified futalosine pathway for menaquinone biosynthesis. While the enzyme from some organisms also has the activity of EC 3.2.2.9, adenosylhomocysteine nucleosidase, the enzyme from Chlamydia trachomatis is specific for 6-amino-6-deoxyfutalosine [7].
5'-methylthioadenosine nucleosidase is implicated in playing a key role in a modified futalosine pathway for menaquinone biosynthesis in Campylobacter jejuni.
Crystal structures of the Helicobacter pylori MTAN enzyme reveal specific interactions between S-adenosylhomocysteine and the 5'-alkylthio binding subsite.
Structural and biochemical characterization of Chlamydia trachomatis hypothetical protein CT263 supports that menaquinone synthesis occurs through the futalosine pathway.