3OKA: Crystal Structure Of Corynebacterium Glutamicum Pimb' In Complex With Gdp-Man (Triclinic Crystal Form)

Long term survival of the pathogen Mycobacterium tuberculosis in humans is linked to the immunomodulatory potential of its complex cell wall glycolipids, which include the phosphatidylinositol mannoside (PIM) series as well as the related lipomannan and lipoarabinomannan glycoconjugates. PIM biosynthesis is initiated by a set of cytosolic alpha-mannosyltransferases, catalyzing glycosyl transfer from the activated saccharide donor GDP-alpha-D-mannopyranose to the acceptor phosphatidyl-myo-inositol (PI) in an ordered and regio-specific fashion. Herein, we report the crystal structure of mannosyltransferase Corynebacterium glutamicum PimB' in complex with nucleotide to a resolution of 2.0 A. PimB' attaches mannosyl selectively to the 6-OH of the inositol moiety of PI. Two crystal forms and GDP- versus GDP-alpha-d-mannopyranose-bound complexes reveal flexibility of the nucleotide conformation as well as of the structural framework of the active site. Structural comparison, docking of the saccharide acceptor, and site-directed mutagenesis pin regio-selectivity to a conserved Asp residue in the N-terminal domain that forces presentation of the correct inositol hydroxyl to the saccharide donor.
PDB ID: 3OKADownload
MMDB ID: 84912
PDB Deposition Date: 2010/8/24
Updated in MMDB: 2010/10
Experimental Method:
x-ray diffraction
Resolution: 2.2  Å
Source Organism:
Corynebacterium glutamicum
Similar Structures:
Biological Unit for 3OKA: dimeric; determined by author
Molecular Components in 3OKA
Label Count Molecule
Proteins (2 molecules)
Gdp-mannose-dependent Alpha-(1-6)-phosphatidylinositol Monomannoside Mannosyltransferase(Gene symbol: NCgl2106)
Molecule annotation
N-terminal His-affinity TAG
Molecule annotation
Chemicals (6 molecules)
* Click molecule labels to explore molecular sequence information.

Citing MMDB