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Structure of the Mycobacterium smegmatis α‐maltose‐1‐phosphate synthase GlgM
Author(s) -
Syson Karl,
Stevenson Clare E. M.,
Lawson David M.,
Bornemann Stephen
Publication year - 2020
Publication title -
acta crystallographica section f
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.572
H-Index - 37
ISSN - 2053-230X
DOI - 10.1107/s2053230x20004343
Subject(s) - mycobacterium smegmatis , maltose , biochemistry , enzyme , glycogen , chemistry , glycogen synthase , biology , mycobacterium tuberculosis , tuberculosis , medicine , pathology
Mycobacterium tuberculosis produces glycogen (also known as α‐glucan) to help evade human immunity. This pathogen uses the GlgE pathway to generate glycogen rather than the more well known glycogen synthase GlgA pathway, which is absent in this bacterium. Thus, the building block for this glucose polymer is α‐maltose‐1‐phosphate rather than an NDP‐glucose donor. One of the routes to α‐maltose‐1‐phosphate is now known to involve the GlgA homologue GlgM, which uses ADP‐glucose as a donor and α‐glucose‐1‐phosphate as an acceptor. To help compare GlgA (a GT5 family member) with GlgM enzymes (GT4 family members), the X‐ray crystal structure of GlgM from Mycobacterium smegmatis was solved to 1.9 Å resolution. While the enzymes shared a GT‐B fold and several residues responsible for binding the donor substrate, they differed in some secondary‐structural details, particularly in the N‐terminal domain, which would be expected to be largely responsible for their different acceptor‐substrate specificities.