• K Dharmalingam

      Articles written in Journal of Biosciences

    • Molecular cloning and sequencing of mcrA locus and identification of McrA protein inEscherichia coli

      R Ramalingam Ranjan Prasad R Shivapriya K Dharmalingam

      More Details Abstract Fulltext PDF

      The Mcr systems (previously known as Rgl systems) ofEscherichia coli recognize and cleave specific sequences carrying methylated or hydroxymethylated cytosines. We have cloned the mcrA gene and determined its nucleotide sequence. An 831 base pair sequence encodes the McrA protein. Analysis of the sequence data reveals that there arc additional ORFs internal to the above. A phage T7 expression system was used to determine the protein products encoded by the cloned mcrA gene. The results clearly show that a 31 kDa polypeptide is responsible for McrA activity. This is in agreement with the molecular weight deduced from sequence data. McrA protein was found to be localized in the outer membrane ofEscherichia coli. To our knowledge this is the first restriction enzyme localized in the outer membraneof Escherichia coli.

    • Genetic instability inStreptomyces

      K Dharmalingam J Cullum

      More Details Abstract Fulltext PDF

      Genetic instability is very common amongStreptomyces strains and the affected strains display several distinctive phenotypes. In several cases DNA rearrangements, specifically deletions and amplifications of specific segments of DNA, were demonstrated. Depending upon the reproducible amplification of a segment in independent isolates one could predict the basic structural elements involved in the amplification process. In the case ofS. lividans 66,5.7 kb amplifiable DNA sequence is located near the end of the linear chromosome. Amplification of this sequence and deletion of the chromosome linked to it leads to the creation of a new end or in some cases even circularisation of the chromosome occurs. A model incorporating these aspects is discussed. The possible involvement of proteins encoded by the amplifiable region is also discussed.

  • Journal of Biosciences | News

    • Editorial Note on Continuous Article Publication

      Posted on July 25, 2019

      Click here for Editorial Note on CAP Mode

© 2017-2019 Indian Academy of Sciences, Bengaluru.