Parvin: Difference between revisions
No edit summary |
No edit summary |
||
| Line 21: | Line 21: | ||
===C-terminal CH domain=== | ===C-terminal CH domain=== | ||
The [[CH domain|calponin-homology (CH) domains]] are helical structural units around 100 amino acids long. They comprise at least four helices, three of them forming a helical bundle. CH domains usually comprise elements of big multidomain proteins and are present either in singlet<ref>PMID: 19459066</ref> or duplex/tandem arrangement.<ref>PMID: 19565353</ref> The tandem arrangement of CH domains is often associated with F-actin binding<ref>PMID: 9708889</ref><ref>PMID: 18952167</ref> (and is thus called actin-binding domain or ABD), but generally CH domains seem to be characterized by functional plasticity and ability to bind various structural motifs.<ref>PMID: 11911887</ref> In the case of alpha-parvin, the interactions of CH domains with both F-actin and other partners (paxillin, ILK) are observed. The interactions with paxillin and ILK are mediated by a single CH domain, the C-terminal one. This domain has attracted most attention. While no full-length structure of alpha-parvin has been solved to date, the structure of the C-terminal CH domain, on its own<ref>PMID: 18940607</ref> and in complexes (with paxillin<ref>PMID: 18940607</ref><ref>PMID: 18508764</ref> and the pseudokinase domain of ILK<ref>PMID: 20005845</ref>) are available. | The [[CH domain|calponin-homology (CH) domains]] are helical structural units around 100 amino acids long. They comprise at least four helices, three of them forming a helical bundle. CH domains usually comprise elements of big multidomain proteins and are present either in singlet<ref>PMID: 19459066</ref> or duplex/tandem arrangement.<ref>PMID: 19565353</ref> The tandem arrangement of CH domains is often associated with F-actin binding<ref>PMID: 9708889</ref><ref>PMID: 18952167</ref> (and is thus called actin-binding domain or ABD), but generally CH domains seem to be characterized by functional plasticity and ability to bind various structural motifs.<ref>PMID: 11911887</ref> In the case of alpha-parvin, the interactions of CH domains with both F-actin and other partners (paxillin, ILK) are observed. The interactions with paxillin and ILK are mediated by a single CH domain, the C-terminal one. This domain has attracted most attention. While no full-length structure of alpha-parvin has been solved to date, the structure of the C-terminal CH domain, on its own<ref>PMID: 18940607</ref> and in complexes (with paxillin<ref>PMID: 18940607</ref><ref>PMID: 18508764</ref> and the pseudokinase domain of ILK<ref>PMID: 20005845</ref>) are available. | ||
[[Image:Consurf_key_small.gif|right]][[2vzc]] shows the structure of the <scene name='User:Marcin_Jozef_Suskiewicz/Sandbox_Parvin//Parvin/1'>C-terminal CH domain of alpha-parvin</scene> at around 1.05 Å. When a sequence alignment of alpha-parvin with all its sequence homologues is performed and the protein is labeled according to <scene name='User:Marcin_Jozef_Suskiewicz/Sandbox_Parvin//Parvin/3'>the degree of sequence conservation</scene>, one can see that the highest conservation is exhibited by the residues located in <scene name='User:Marcin_Jozef_Suskiewicz/Sandbox_Parvin//Parvin/5'>the core helices</scene>, and less is seen in linker helices and loops. When the <scene name='User:Marcin_Jozef_Suskiewicz/Sandbox_Parvin//Parvin_overlap/1'>structural superposition</scene> of the C-terminal CH domain of alpha-parvin and one of the CH domains of alpha-actinin 3 ([[ | [[Image:Consurf_key_small.gif|right]][[2vzc]] shows the structure of the <scene name='User:Marcin_Jozef_Suskiewicz/Sandbox_Parvin//Parvin/1'>C-terminal CH domain of alpha-parvin</scene> at around 1.05 Å. When a sequence alignment of alpha-parvin with all its sequence homologues is performed and the protein is labeled according to <scene name='User:Marcin_Jozef_Suskiewicz/Sandbox_Parvin//Parvin/3'>the degree of sequence conservation</scene>, one can see that the highest conservation is exhibited by the residues located in <scene name='User:Marcin_Jozef_Suskiewicz/Sandbox_Parvin//Parvin/5'>the core helices</scene>, and less is seen in linker helices and loops. When the <scene name='User:Marcin_Jozef_Suskiewicz/Sandbox_Parvin//Parvin_overlap/1'>structural superposition</scene> of the C-terminal CH domain of alpha-parvin and one of the CH domains of alpha-actinin 3 ([[1wku]]) is performed, a good overlap is observed despite low sequence homology (≤26% identity), as represented by the RMSD of 1.19 Å for 103 equivalent C<sup>α</sup> positions.<ref>PMID: 18940607</ref> This suggests that the structural framework of CH domain is quite robust. The most diverged fragments in the C-terminal CH domain of alpha-parvin correspond to 1) an <scene name='User:Marcin_Jozef_Suskiewicz/Sandbox_Parvin//Parvin_overlap/3'>additional helix</scene> (so called N-terminal linker helix) located at the N-terminal end of the domain and not observed in any other CH domain and 2) a <scene name='User:Marcin_Jozef_Suskiewicz/Sandbox_Parvin//Parvin_overlap/5'>long loop</scene> between two of the helices. The loop in question contains a <scene name='User:Marcin_Jozef_Suskiewicz/Sandbox_Parvin//Parvin_overlap/6'>3-amino acid insertion</scene> (313-315). | ||