The primary and secondary structure analyses were performed OSI744 using the protparam tool on ExPASy server (Bairoch et al., 2005) and psipred (Jones,

1999), respectively. The tertiary structure of CspD from Ant5-2 was generated by the modeller software from hhpred alignments on HHpred servers (Soding et al., 2005; Eswar et al., 2006). The significance of the protein structure similarity was measured by TM-score calculated by T-align, a more sensitive method than root-mean-square-deviation (Zhang & Skolnick, 2005). The protein–protein docking was performed using the hex 5.1 software according to its manual (Ritchie & Venkatraman, 2010). During the initial 4 h, Ant5-2 cultures exhibited faster growth rates at 22 and 37 °C than at 15 °C (Fig. 1). Within 20 h of incubation at 15, 22 and 37 °C, the cultures grew exponentially and reached stationary phase. However, the culture at 37 °C exhibited a decline in growth after 48 h of incubation. In contrast, the cultures maintained at −1 and 4 °C did not show

any significant cell proliferation for 24 and 4 h, respectively. Thereafter, the culture at 4 °C exhibited exponential growth and reached stationary phase within 72 h. A slow but steady exponential growth of the culture at −1 °C was noticed after incubation for 24 h. After one freeze–thaw cycle, increased survival was observed when Ant5-2 was exposed to 4 °C before freezing. The cultures transferred to 4 °C showed 94.1% survival compared with the 48.9% survival of cultures incubated see more at 22 °C (Supporting however Information, Fig. S1). The autoradiogram exhibited expression of a ∼7.28-kDa Csp

(CspD) at all temperatures (Fig. S2). The immunoblot results showed that the expression of CspD in Ant5-2 was both time- and growth phase-dependent (Fig. 2a). Its expression increased at 37 °C and UVC exposure (Fig. 2b and c). A 204-bp DNA fragment encompassing the entire ORF of the cspD gene (accession no. HQ873479) was PCR amplified. The deduced amino acid sequence exhibited 100% identity with the cold shock transcription regulator of J. lividum DSM 1522 and >98% sequence identity with the RNA chaperone, transcription antiterminator of Herminiimonas arsenicoxydans and with Csps from different bacteria belonging to class Betaproteobacteria (Figs 3 and Fig. S3). The CspD from Ant5-2 showed highest identity and similarity to E. coli CspE (67/83%) and E. coli CspD (56/74%) when compared with Csps from E. coli, B. subtilis and Pseudomonas sp. 30/3 (Fig. 3). PCR amplification of the cspA family of genes in Ant5-2 genomic DNA using CSPU5 and CSPU3 universal primers (Francis and Stewart, 1997) resulted in negative outcome (Fig. S4).