Vepatu Shankar

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We report the identification of a new cell wall-associated protein of Enterococcus faecalis. Studies on the distribution of the gene encoding this novel surface protein, Esp, reveal a significant (P < 0.001) enrichment in infection-derived E. faecalis isolates. Interestingly, the esp gene was not identified in any of 34 clinical E. faecium isolates or in 4(More)
Ribonucleases are ubiquitous in distribution. Ribonucleases that hydrolyse RNA to 3' mononucleotides via 2', 3' cyclic nucleotides are classified into three groups, RNase A, RNase T1, and RNase T2 families. Apart from salvage of cellular or extracellular RNAs, RNases participate in vital cellular functions such as DNA replication, transcription and RNA(More)
Single-strand-specific nucleases, which act on single-stranded nucleic acids and single-stranded regions in double-stranded nucleic acids, are multifunctional enzymes and are ubiquitous in distribution. They find wide application as analytical tools in molecular biology research, although enzymes such as P1 nuclease are also used for production of flavor(More)
Sugar non-specific endonucleases are multifunctional enzymes and are widespread in distribution. Apart from nutrition, they have also been implicated in cellular functions like replication, recombination and repair. Their ability to recognize different DNA structures has also been exploited for the determination of nucleic acid structure. Although more than(More)
An extracellular nuclease from Streptomyces thermonitrificans (designated as nuclease Stn alpha) was purified to homogeneity with an overall yield of 2.8%. The Mr of the purified enzyme was 39.6 kDa. The purified enzyme showed an exclusive requirement of Mn2+ for its activity but is not a metalloprotein. The optimum pH for ds- and ssDNA hydrolysis were 7.0(More)
A partial cDNA (pAM1) encoding a major airway mucin glycoprotein with novel tandem repetitive sequence has recently been cloned (Shankar, V., M. S. Gilmore, R. C. Elkins, and G. P. Sachdev. 1994. Biochem. J. 300:295-298). In this article, we report additional new sequence derived by 3'-rapid amplification of cDNA ends technique. The sequence corresponds to(More)
Highly specific affinity-purified polyclonal antibodies against deglycosylated human tracheobronchial mucin was used to select immunoreactive clones from a Uni-ZAP cDNA expression library prepared from normal human tracheal mRNA. The largest of three positive clones, designated pAM1, which reacted strongly with the polyclonal antibodies, was further(More)
A strain of Rhizopus stolonifer produced high levels of extracellular ribonuclease (RNase) when grown on YPG (yeast extract, peptone, glucose) medium. Influence of various medium components on the production of extracellular RNase activity showed that divalent metal ions had a marked effect on growth and enzyme production. Maximum enzyme activity (3000(More)
The conformational stability of RNase Rs was determined with chemical and thermal denaturants over the pH range of 1-10. Equilibrium unfolding with urea showed that values of D(1/2) (5.7 M) and DeltaG(H(2)O) (12.8 kcal/mol) were highest at pH 5.0, its pI and the maximum conformational stability of RNase Rs was observed near pH 5.0. Denaturation with(More)
An extracellular nuclease from Rhizopus stolonifer (designated as nuclease Rsn) was purified to homogeneity by chromatography on DEAE-cellulose followed by Blue Sepharose. The M(r) of the purified enzyme determined by native PAGE was 67¿ omitted¿000 and it is a tetramer and each protomer consists of two unidentical subunits of M(r) 21¿ omitted¿000 and 13¿(More)