1SXQ

BGT in complex with a 13mer DNA containing a central C:G base pair and UDP

Summary for 1SXQ

• Entry DOI: 10.2210/pdb1sxq/pdb
• Related: 1IXY 1M5R 1SXP
• Descriptor: 5'-D(*AP*AP*AP*AP*AP*AP*GP*TP*TP*TP*TP*TP*T)-3', 5'-D(*AP*AP*AP*AP*AP*AP*CP*TP*TP*TP*TP*TP*T)-3', DNA beta-glucosyltransferase, ... (5 entities in total)
• Functional Keywords: flipped-out base, transferase-dna complex, transferase/dna
• Biological source: Enterobacteria phage T4
• Total number of polymer chains: 6
• Total formula weight: 98122.62

Authors

Lariviere, L.,Morera, S. (deposition date: 2004-03-31, release date: 2004-06-22, Last modification date: 2024-02-14)

Primary citation

Lariviere, L.,Morera, S.
Structural evidence of a passive base flipping mechanism for {beta}-Glucosyltransferase
J.Biol.Chem., 279:34715-34720, 2004

PubMed Abstract: Beta-glucosyltransferase (BGT) is a DNA-modifying enzyme and a glycosyltransferase. This inverting enzyme transfers glucose from UDP-glucose to the 5-hydroxymethyl cytosine bases of T4 phage DNA. From previous structural analyses we showed that Asp-100 and Asn-70 were, respectively, the catalytic base and the key residue for specific DNA recognition (Larivière, L., Gueguen-Chaignon, V., and Moréra, S. (2003) J. Mol. Biol. 330, 1077-1086). Here, we supply biochemical evidence supporting their essential roles in catalysis. We have also shown previously that BGT uses a base-flipping mechanism to access 5-hydroxymethyl cytosine (Larivière, L., and Moréra, S. (2002) J. Mol. Biol. 324, 483-490). Whether it is an active or a passive process remains unclear, as is the case for all DNA cleaving and modifying enzymes. Here, we report two crystal structures: (i) BGT in complex with a 13-mer DNA containing an A:G mismatch and (ii) BGT in a ternary complex with UDP and an oligonucleotide containing a single central G:C base pair. The binary structure reveals a specific complex with the flipped-out, mismatched adenine exposed to the active site. Unexpectedly, the other structure shows the non-productive binding of an intermediate flipped-out base. Our structural analysis provides clear evidence for a passive process.

PubMed: 15178685
DOI: 10.1074/jbc.M404394200

Experimental method

X-RAY DIFFRACTION (1.8 Å)