Protein schematics and amino acid sequence alignments of D. radiodurans R1 SSB protein and other SSB proteins. A) Schematic representation of the D. radiodurans R1 SSB protein and other SSB proteins highlighting the OB fold regions. The Drad, Taq, TthHB8 and TthVK1 SSB proteins contain two OB folds each. The characteristic motifs that make up an OB fold are highlighted with open boxes/arrows and numbered. The Gmet, Neur, PaerPAO1 and EcoliK12 SSB proteins contain one OB fold each and align with both the N-terminal OB fold and the C-terminal OB fold of the proteins that contain two OB folds. Only the C-terminal alignments are shown. The structural assignments are according to the OB fold rule defined by Murzin [11, 32]. B) Amino acid sequence alignment of D. radiodurans R1 SSB protein and other SSB proteins from closely and distantly related bacteria. The Drad, Taq, TthHB8 and TthVK1 SSB protein sequences are divided into N- and C-terminal fragments in order to highlight that each fragment contains an OB fold. The arrows indicate β-sheets and the rectangle indicates the α-helix contained in the secondary structure of the OB fold of SSB protein from E. coli strain K12 [11, 32]. Sequence identity is shown by white fonts on black boxes, and sequence similarity is shown by black font on gray boxes. Sequence similarity is defined by the following amino acid groupings: STA, NEQK, NHQK, NDEQ, QHRK, MILV, MILF, HY, FYW. Abbreviations: Drad-N or -C: D. radiodurans strain R1, N- or C- terminal fragment; Taq-N or -C: T. aquaticus, N- or C- terminal fragment; TthHB8-N or -C: T. thermophilus strain HB8, N- or C- terminal fragment; TthVK1-N or -C: T. thermophilus strain VK1, N- or C- terminal fragment; Gmet: Geobacter metallireducens; Neur: Nitrosomonas europaea ATCC 19718; PaerPAO1: Pseudomonas aeruginosa PAO1. EcoliK12: E. coli strain K12.