Open AccessIsolation and characterization of the carbohydrate moiety bound to N ‐7‐mercaptoheptanoyl‐ O ‐threonine phosphate
Author(s) -
Sauer F.D.,
Blackwell B.A.,
Kramer J.K.G.,
Marsden B.J.
Publication year - 1990
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.1574-6968.1990.tb04933.x
Subject(s) - disaccharide , chemistry , moiety , threonine , stereochemistry , phosphate , fast atom bombardment , nuclear magnetic resonance spectroscopy , molecule , phosphoric acid , carbohydrate , mass spectrometry , organic chemistry , chromatography , serine , enzyme
Component B ( N ‐7‐mercaptoheptanoyl‐threonine‐ O ‐3‐phosphate) (HS‐HTP) which is an absolute requirement in the methylcoenzyme M methylreductase reaction was found to be part of a complex UDP‐disaccharide when isolated carefully from cell‐free supernant of Methanobacterium thermoautotrophicum . The site of attachment of HS‐HTP to the UDP‐disaccharide was through a carboxylic‐phosphoric anhydride linkage of the C‐6 mannosaminuronic acid to the phosphate group in HS‐HTP. This bond is quite labile and this may account for the fact that the intact molecule, called methyl reducing factor (MRF) was not isolated previously. The structure of MRF was determined by combined fast atom bombardment mass spectrometry and 1 H‐, 13 C‐, and 31 P‐NMR spectroscopy and assigned as: uridine 5′‐[ N ‐7‐mercaptoheptanoyl‐ O ‐3‐phosphothreonine(2‐acetamido‐2‐deoxy‐ β ‐mannopyranuronosyl)acid anhydride]‐(1 → 4)‐ O ‐2‐acetamido‐2‐deoxy α ‐glucopyranosyl diphosphate.