Nucleic Acids Research Advance Access originally published online on August 21, 2007
Nucleic Acids Research 2007 35(17):5658-5671; doi:10.1093/nar/gkm558
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Nucleic Acids Research, 2007, Vol. 35, No. 17 5658-5671
© 2007 The Author(s)
This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/2.0/uk/) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.
Structural Biology |
The RAGNYA fold: a novel fold with multiple topological variants found in functionally diverse nucleic acid, nucleotide and peptide-binding proteins
National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD 20894, USA
*To whom correspondence should be addressed. Email: aravind{at}ncbi.nlm.nih.gov
Received May 1, 2007. Revised July 2, 2007. Accepted July 9, 2007.
Using sensitive structure similarity searches, we identify a shared 
+ß fold, RAGNYA, principally involved in nucleic acid, nucleotide or peptide interactions in a diverse group of proteins. These include the Ribosomal proteins L3 and L1, ATP-grasp modules, the GYF domain, DNA-recombination proteins of the NinB family from caudate bacteriophages, the C-terminal DNA-interacting domain of the Y-family DNA polymerases, the uncharacterized enzyme AMMECR1, the siRNA silencing repressor of tombusviruses, tRNA Wybutosine biosynthesis enzyme Tyw3p, DNA/RNA ligases and related nucleotidyltransferases and the Enhancer of rudimentary proteins. This fold exhibits three distinct circularly permuted versions and is composed of an internal repeat of a unit with two-strands and a helix. We show that despite considerable structural diversity in the fold, its representatives show a common mode of nucleic acid or nucleotide interaction via the exposed face of the sheet. Using this information and sensitive profile-based sequence searches: (1) we predict the active site, and mode of substrate interaction of the Wybutosine biosynthesis enzyme, Tyw3p, and a potential catalytic role for AMMECR1. (2) We provide insights regarding the mode of nucleic acid interaction of the NinB proteins, and the evolution of the active site of classical ATP-grasp enzymes and DNA/RNA ligases. (3) We also present evidence for a bacterial origin of the GYF domain and propose how this version of the fold might have been utilized in peptide interactions in the context of nucleoprotein complexes.