1MC3

CRYSTAL STRUCTURE OF RFFH

Summary for 1MC3

• Entry DOI: 10.2210/pdb1mc3/pdb
• Descriptor: GLUCOSE-1-PHOSPHATE THYMIDYLYLTRANSFERASE, MAGNESIUM ION, THYMIDINE-5'-TRIPHOSPHATE, ... (4 entities in total)
• Functional Keywords: glucose-1-phosphate thymidylytransferase, rffh, montreal-kingston bacterial structural genomics initiative, bsgi, structural genomics, transferase
• Biological source: Escherichia coli
• Total number of polymer chains: 2
• Total formula weight: 67583.06

Authors

Sivaraman, J.,Sauve, V.,Matte, A.,Cygler, M.,Montreal-Kingston Bacterial Structural Genomics Initiative (BSGI) (deposition date: 2002-08-05, release date: 2002-11-20, Last modification date: 2024-10-30)

Primary citation

Sivaraman, J.,Sauve, V.,Matte, A.,Cygler, M.
Crystal Structure of Escherichia coli Glucose-1-Phosphate Thymidylyltransferase (RffH) Complexed with dTTP and Mg2+
J.BIOL.CHEM., 277:44214-44219, 2002

PubMed Abstract: The enzyme glucose-1-phosphate thymidylyltransferase (RffH), the product of the rffh gene, catalyzes one of the steps in the synthesis of enterobacterial common antigen (ECA), a cell surface glycolipid found in Gram-negative enteric bacteria. In Escherichia coli two gene products, RffH and RmlA, catalyze the same enzymatic reaction and are homologous in sequence; however, they are part of different operons and function in different pathways. We report the crystal structure of RffH bound to deoxythymidine triphosphate (dTTP), the phosphate donor, and Mg(2+), refined at 2.6 A to an R-factor of 22.3% (R(free) = 28.4%). The crystal structure of RffH shows a tetrameric enzyme best described as a dimer of dimers. Each monomer has an overall alpha/beta fold and consists of two domains, a larger nucleotide binding domain (residues 1-115, 222-291) and a smaller sugar-binding domain (116-221), with the active site located at the domain interface. The Mg(2+) ion is coordinated by two conserved aspartates and the alpha-phosphate of deoxythymidine triphosphate. Its location corresponds well to that in a structurally similar domain of N-acetylglucosamine-1-phosphate uridylyltransferase (GlmU). Analysis of the RffH, RmlA, and GlmU complexes with substrates and products provides an explanation for their different affinities for Mg(2+) and leads to a proposal for the dynamics along the reaction pathway.

PubMed: 12171937
DOI: 10.1074/jbc.M206932200

Experimental method

X-RAY DIFFRACTION (2.6 Å)