Sandbox Reserved 939
From Proteopedia
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In the 65K C-terminal RRM structure, residues 417–501 adopt a typical RRM fold, with an antiparallel four-stranded β-sheet packed against two α-helices. In addition to these canonical elements, the 65K C-terminal RRM contains <scene name='57/579709/Shorthelix/1'>a short helix</scene> between the α1 helix and the β2 strand and a <scene name='57/579709/Betahairpin/2'>beta-hairpin</scene> in the loop connecting β2 and α2. Interestingly, as shown by electrophoretic mobility shift assays (EMSA), the core RRM fold of U11/U12-65K alone fails to bind to U12 snRNA. The core fold is stabilized by an N-terminal expansion comprising residues 380–417, which are required for RNA binding. <scene name='57/579709/Expansion/1'>The N-terminal expansion</scene> folds into two α-helices, a 3<sub>10</sub>-helix and a long loop that connects the expansion to the β1 strand. | In the 65K C-terminal RRM structure, residues 417–501 adopt a typical RRM fold, with an antiparallel four-stranded β-sheet packed against two α-helices. In addition to these canonical elements, the 65K C-terminal RRM contains <scene name='57/579709/Shorthelix/1'>a short helix</scene> between the α1 helix and the β2 strand and a <scene name='57/579709/Betahairpin/2'>beta-hairpin</scene> in the loop connecting β2 and α2. Interestingly, as shown by electrophoretic mobility shift assays (EMSA), the core RRM fold of U11/U12-65K alone fails to bind to U12 snRNA. The core fold is stabilized by an N-terminal expansion comprising residues 380–417, which are required for RNA binding. <scene name='57/579709/Expansion/1'>The N-terminal expansion</scene> folds into two α-helices, a 3<sub>10</sub>-helix and a long loop that connects the expansion to the β1 strand. | ||
| - | Most RRMs interact with RNA through their β-sheet surface, which contains two highly conserved sequence motifs, called RNP1 and RNP2, located in the central β3 and β1 strands, respectively. In many cases, additional elements such as the loops connecting various secondary structure elements, or the N- or C-terminal extensions outside the core RRM fold are also involved in RNA binding. The structural basis of RNA binding of the U11/U12-65K C-terminal RRM appears to be similar to that of canonical RRMs, such as the U1A N-terminal RRM. Because of the absence of RNA in the 65K structure, direct structural information on RNA–protein contacts is not available. However, based on sequence alignment, Netter ''et al.'' identified several residues analogous to those involved in RNA binding in the U1A protein, mutated these residues and tested their effect on RNA binding using gel-shift assays<ref name="netter"/>. | + | Most RRMs interact with RNA through their β-sheet surface, which contains two highly conserved sequence motifs, called RNP1 and RNP2, located in the central β3 and β1 strands, respectively<ref>PMID:15853797</ref><ref>PMID:22278943</ref>. In many cases, additional elements such as the loops connecting various secondary structure elements, or the N- or C-terminal extensions outside the core RRM fold are also involved in RNA binding. The structural basis of RNA binding of the U11/U12-65K C-terminal RRM appears to be similar to that of canonical RRMs, such as the U1A N-terminal RRM. Because of the absence of RNA in the 65K structure, direct structural information on RNA–protein contacts is not available. However, based on sequence alignment, Netter ''et al.'' identified several residues analogous to those involved in RNA binding in the U1A protein, mutated these residues and tested their effect on RNA binding using gel-shift assays<ref name="netter"/>. |
==References== | ==References== | ||
<references /> | <references /> | ||
Revision as of 17:05, 18 May 2014
| This Sandbox is Reserved from 01/04/2014, through 30/06/2014 for use in the course "510042. Protein structure, function and folding" taught by Prof Adrian Goldman, Tommi Kajander, Taru Meri, Konstantin Kogan and Juho Kellosalo at the University of Helsinki. This reservation includes Sandbox Reserved 923 through Sandbox Reserved 947. |
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