Please use this identifier to cite or link to this item: http://scholarbank.nus.edu.sg/handle/10635/14870
Title: Structure determination and analysis of scavenger decapping enzymes DcpS
Authors: CHEN NAN
Keywords: X-ray crystallography; protein structure; mRNA decay; mRNA decapping; scavenger mRNA decapping
Issue Date: 10-Nov-2005
Source: CHEN NAN (2005-11-10). Structure determination and analysis of scavenger decapping enzymes DcpS. ScholarBank@NUS Repository.
Abstract: Eukaryotic cells utilize DcpS, a scavenger decapping enzyme to degrade the residual cap structure following the 3a?? to 5a?? mRNA decay, thereby preventing the premature decapping of the capped long mRNA and misincorporation of methylated nucleotides in nucleic acids. Human DcpS was cloned and expressed as GST-fusion protein. The recombinant protein was purified and crystallized. Three dimensional structures of DcpS in ligand-free form and in complex with m7GDP were solved by X-ray crystallography method. Comparisons of these two structures and known structure of DcpS in complex with cap m7GpppG showed conformational changes in different enzyme state. apo-DcpS is a symmetric dimer, strikingly different from the asymmetric dimer observed in the structures of DcpS with bound cap analogues. DcpS with bound m7GDP is an asymmetric dimer in which the closed state appears to be the substrate-bound complex whereas the open state mimics the product-bound complex. Structural comparisons combined with mutational analysis suggest a dynamic mechanism for scavenger mRNA decapping.
URI: http://scholarbank.nus.edu.sg/handle/10635/14870
Appears in Collections:Master's Theses (Open)

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