1zdh
MS2 COAT PROTEIN/RNA COMPLEX
Structural highlights
FunctionCAPSD_BPMS2 Self-assembles to form the T=3 icosahedral virus shell that protects the viral nucleic acid. Acts as a translational repressor by binding with high specificity to a single stem-loop structure in the genomic RNA that contains the initiation codon of the gene for the viral replicase. Involved in virus assembly through the interaction between a capsid protein dimer and the multiple packaging signals present in the RNA genome.[1] [2] [3] [4] [5] [6] Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedCrystal structures of two complexes between recombinant MS2 capsids and RNA operator fragments have been determined at 2.7 A resolution. The coat protein of the RNA bacteriophage MS2 is bifunctional; it forms the icosahedral virus shell to protect the viral nucleic acid and it acts as a translational repressor by binding with high specificity to a unique site on the RNA, a single stem-loop structure, containing the initiation codon of the gene for the viral replicase. In order to determine the structure of these protein-RNA complexes, we have used chemically synthesized variants of the stem-loop fragment and soaked them into crystals of recombinant capsids. The RNA stem-loop, as bound to the protein, forms a crescent-like structure and interacts with the surface of the beta-sheet of a coat protein dimer. It makes protein contacts with seven phosphate groups on the 5' side of the stem-loop, with a pyrimidine base at position -5, which stacks onto a tyrosine, and with two exposed adenine bases, one in the loop and one at a bulge in the stem. Replacement of the wild-type uridine with a cytosine at position -5 increases the affinity of the RNA to the dimer significantly. The complex with RNA stem-loop having cytosine at this position differs from that of the wild-type complex mainly by having one extra intramolecular RNA interaction and one extra water-mediated hydrogen bond. The three-dimensional structures of two complexes between recombinant MS2 capsids and RNA operator fragments reveal sequence-specific protein-RNA interactions.,Valegard K, Murray JB, Stonehouse NJ, van den Worm S, Stockley PG, Liljas L J Mol Biol. 1997 Aug 1;270(5):724-38. PMID:9245600[7] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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