1m5l: Difference between revisions
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'''Structure of wild-type and mutant internal loops from the SL-1 domain of the HIV-1 packaging signal'''<br /> | '''Structure of wild-type and mutant internal loops from the SL-1 domain of the HIV-1 packaging signal'''<br /> | ||
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==About this Structure== | ==About this Structure== | ||
1M5L is a [http://en.wikipedia.org/wiki/Protein_complex Protein complex] structure of sequences from [http://en.wikipedia.org/wiki/ ]. Full crystallographic information is available from [http:// | 1M5L is a [http://en.wikipedia.org/wiki/Protein_complex Protein complex] structure of sequences from [http://en.wikipedia.org/wiki/ ]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1M5L OCA]. | ||
==Reference== | ==Reference== | ||
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[[Category: sl-1]] | [[Category: sl-1]] | ||
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Revision as of 14:22, 15 February 2008
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Structure of wild-type and mutant internal loops from the SL-1 domain of the HIV-1 packaging signal
Overview
The packaging signal (Psi) of the human immunodeficiency virus type 1, (HIV-1) enables encapsidation of the full-length genomic RNA against a, background of a vast excess of cellular mRNAs. The core HIV-1 Psi is, approximately 109 nucleotides and contains sequences critical for viral, genomic dimerisation and splicing, in addition to the packaging signal. It, consists of a series of stem-loops (termed SL-1 to SL-4), which can be, arranged in a cloverleaf secondary structure. Using a combination of NMR, spectroscopy, UV melting experiments, molecular modeling and phylogenetic, analyses, we have explored the structure of two conserved internal loops, proximal to the palindromic sequence of SL-1. Internal loop A, composed of, six purines, forms a flexible structure that is strikingly similar to the, Rev responsive element motif when bound to Rev protein. This result, suggests that it may function as a protein-binding site. The absolutely, conserved four-purine internal loop B is instead conformationally and, thermodynamically unstable, and exhibits multiple conformations in, solution. By introducing a double AGG to GGA mutation within this loop, its conformation is stabilised to form a new intra-molecular G:A:G, base-triplet. The structure of the GGA mutant explains the relative, instability of the wild-type loop. In a manner analogous to SL-3, we, propose that conformational flexibility at this site may facilitate, melting of the structure during Gag protein capture or genomic RNA, dimerisation.
About this Structure
1M5L is a Protein complex structure of sequences from [1]. Full crystallographic information is available from OCA.
Reference
Structure and stability of wild-type and mutant RNA internal loops from the SL-1 domain of the HIV-1 packaging signal., Greatorex J, Gallego J, Varani G, Lever A, J Mol Biol. 2002 Sep 20;322(3):543-57. PMID:12225748
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