4FIY

Crystal Structure of GlfT2 Complexed with UDP

Summary for 4FIY

• Entry DOI: 10.2210/pdb4fiy/pdb
• Related: 4FIX
• Descriptor: UDP-galactofuranosyl transferase GlfT2, URIDINE-5'-DIPHOSPHATE, MANGANESE (II) ION, ... (5 entities in total)
• Functional Keywords: galactofuranosyltransferase, cazy gt-2 family, glycosyltransferase, carbohydrate binding, membrane, transferase
• Biological source: Mycobacterium tuberculosis
• Total number of polymer chains: 2
• Total formula weight: 148551.90

Authors

Wheatley, R.W.,Zheng, R.B.,Lowary, T.L.,Ng, K.K.S. (deposition date: 2012-06-11, release date: 2012-06-20, Last modification date: 2023-09-13)

Primary citation

Wheatley, R.W.,Zheng, R.B.,Richards, M.R.,Lowary, T.L.,Ng, K.K.
Tetrameric Structure of the GlfT2 Galactofuranosyltransferase Reveals a Scaffold for the Assembly of Mycobacterial Arabinogalactan.
J.Biol.Chem., 287:28132-28143, 2012

PubMed Abstract: Biosynthesis of the mycobacterial cell wall relies on the activities of many enzymes, including several glycosyltransferases (GTs). The polymerizing galactofuranosyltransferase GlfT2 (Rv3808c) synthesizes the bulk of the galactan portion of the mycolyl-arabinogalactan complex, which is the largest component of the mycobacterial cell wall. We used x-ray crystallography to determine the 2.45-Å resolution crystal structure of GlfT2, revealing an unprecedented multidomain structure in which an N-terminal β-barrel domain and two primarily α-helical C-terminal domains flank a central GT-A domain. The kidney-shaped protomers assemble into a C(4)-symmetric homotetramer with an open central core and a surface containing exposed hydrophobic and positively charged residues likely involved with membrane binding. The structure of a 3.1-Å resolution complex of GlfT2 with UDP reveals a distinctive mode of nucleotide recognition. In addition, models for the binding of UDP-galactofuranose and acceptor substrates in combination with site-directed mutagenesis and kinetic studies suggest a mechanism that explains the unique ability of GlfT2 to generate alternating β-(1→5) and β-(1→6) glycosidic linkages using a single active site. The topology imposed by docking a tetrameric assembly onto a membrane bilayer also provides novel insights into aspects of processivity and chain length regulation in this and possibly other polymerizing GTs.

PubMed: 22707726
DOI: 10.1074/jbc.M112.347484

Experimental method

X-RAY DIFFRACTION (3.1 Å)