Accession Number : ADB262660


Title :   Understanding Single-Stranded Telomere End Binding by an Essential Protein


Descriptive Note : Annual summary rept. 1Aug 1999-31 Jul 2000


Corporate Author : COLORADO UNIV AT BOULDER


Personal Author(s) : Anderson, Emily ; Wuttke, Deborah


Full Text : https://apps.dtic.mil/dtic/tr/fulltext/u2/b262660.pdf


Report Date : Aug 2000


Pagination or Media Count : 16


Abstract : Telomeres are the nucleoprotein structures that protect the ends of eukaryotic chromosomes. Telomere length regulation is controlled by the enzyme telomerase and a suite of telomere binding proteins. Anomalous telomeric replication and regulation are implicated in most forms of cancer, while telomeric shortening contributes to cellular aging. Cdcl3p is an essential protein from S. cerevisiae that binds to the single-stranded ends of telomeres with high specificity and affinity. Genetically, Cdcl3p has been shown to protect the end of the chromosome from degradation and to load telomerase. Biochemically, Cdcl3p binds yeast single-stranded telomeric DNA (sstelo DNA) in vitro with high affinity (Kd=O.3 nM) We are investigating the structural basis for high affinity binding and sequence specificity of the single-stranded DNA binding domain. We have expressed and purified the ssDNA binding domain in high yield. Its binding affinity and specificity have been examined with libraries of sstelo DNA randomized at each position. In vitro photocrosslinking experiments have been performed using 5- iodouracil substituted for thymine bases. Proteolytic digestion of the crosslinked products along with micro peptide sequencing have allowed us to identify sites critical for DNA binding. These experiments complement high resolution NMR studies of the protein/DNA complex in progress in our laboratory.


Descriptors :   *CELLS(BIOLOGY) , *BREAST CANCER , PEPTIDES , ENZYMES , DEOXYRIBONUCLEIC ACIDS , CHROMOSOMES , CROSSLINKING(CHEMISTRY) , GENES , CHROMATIN , PROTEINS(SIMPLE)


Subject Categories : Biochemistry
      Genetic Engineering and Molecular Biology
      Anatomy and Physiology
      Medicine and Medical Research


Distribution Statement : APPROVED FOR PUBLIC RELEASE