4CN1

GlgE isoform 1 from Streptomyces coelicolor D394A mutant with maltose- 1-phosphate bound

Summary for 4CN1

• Entry DOI: 10.2210/pdb4cn1/pdb
• Related: 4CN4 4CN6
• Related PRD ID: PRD_900078
• Descriptor: ALPHA-1,4-GLUCAN\: MALTOSE-1-PHOSPHATE MALTOSYLTRANSFERASE 1, alpha-D-glucopyranose-(1-4)-1-O-phosphono-alpha-D-glucopyranose (3 entities in total)
• Functional Keywords: hydrolase, alpha-glucan biosynthesis, glycoside hydrolase family 13_3, drug target
• Biological source: STREPTOMYCES COELICOLOR
• Total number of polymer chains: 2
• Total formula weight: 155886.23

Authors

Syson, K.,Stevenson, C.E.M.,Rashid, A.M.,Saalbach, G.,Tang, M.,Tuukanen, A.,Svergun, D.I.,Withers, S.G.,Lawson, D.M.,Bornemann, S. (deposition date: 2014-01-21, release date: 2014-05-21, Last modification date: 2023-12-20)

Primary citation

Syson, K.,Stevenson, C.E.M.,Rashid, A.M.,Saalbach, G.,Tang, M.,Tuukkanen, A.,Svergun, D.I.,Withers, S.G.,Lawson, D.M.,Bornemann, S.
Structural Insight Into How Streptomyces Coelicolor Maltosyl Transferase Glge Binds Alpha-Maltose 1-Phosphate and Forms a Maltosyl-Enzyme Intermediate.
Biochemistry, 53:2494-, 2014

PubMed Abstract: GlgE (EC 2.4.99.16) is an α-maltose 1-phosphate:(1→4)-α-d-glucan 4-α-d-maltosyltransferase of the CAZy glycoside hydrolase 13_3 family. It is the defining enzyme of a bacterial α-glucan biosynthetic pathway and is a genetically validated anti-tuberculosis target. It catalyzes the α-retaining transfer of maltosyl units from α-maltose 1-phosphate to maltooligosaccharides and is predicted to use a double-displacement mechanism. Evidence of this mechanism was obtained using a combination of site-directed mutagenesis of Streptomyces coelicolor GlgE isoform I, substrate analogues, protein crystallography, and mass spectrometry. The X-ray structures of α-maltose 1-phosphate bound to a D394A mutein and a β-2-deoxy-2-fluoromaltosyl-enzyme intermediate with a E423A mutein were determined. There are few examples of CAZy glycoside hydrolase family 13 members that have had their glycosyl-enzyme intermediate structures determined, and none before now have been obtained with a 2-deoxy-2-fluoro substrate analogue. The covalent modification of Asp394 was confirmed using mass spectrometry. A similar modification of wild-type GlgE proteins from S. coelicolor and Mycobacterium tuberculosis was also observed. Small-angle X-ray scattering of the M. tuberculosis enzyme revealed a homodimeric assembly similar to that of the S. coelicolor enzyme but with slightly differently oriented monomers. The deeper understanding of the structure-function relationships of S. coelicolor GlgE will aid the development of inhibitors of the M. tuberculosis enzyme.

PubMed: 24689960
DOI: 10.1021/BI500183C

Experimental method

X-RAY DIFFRACTION (2.55 Å)