1ydx
From Proteopedia
(New page: 200px<br /><applet load="1ydx" size="450" color="white" frame="true" align="right" spinBox="true" caption="1ydx, resolution 2.30Å" /> '''Crystal structure of...) |
|||
| Line 1: | Line 1: | ||
| - | [[Image:1ydx.gif|left|200px]]<br /><applet load="1ydx" size=" | + | [[Image:1ydx.gif|left|200px]]<br /><applet load="1ydx" size="350" color="white" frame="true" align="right" spinBox="true" |
caption="1ydx, resolution 2.30Å" /> | caption="1ydx, resolution 2.30Å" /> | ||
'''Crystal structure of Type-I restriction-modification system S subunit from M. genitalium'''<br /> | '''Crystal structure of Type-I restriction-modification system S subunit from M. genitalium'''<br /> | ||
==Overview== | ==Overview== | ||
| - | The crystal structure of the eubacteria Mycoplasma genitalium ORF MG438 | + | The crystal structure of the eubacteria Mycoplasma genitalium ORF MG438 polypeptide, determined by multiple anomalous dispersion and refined at 2.3 A resolution, reveals the organization of S subunits from the Type I restriction and modification system. The structure consists of two globular domains, with about 150 residues each, separated by a pair of 40 residue long antiparallel alpha-helices. The globular domains correspond to the variable target recognition domains (TRDs), as previously defined for S subunits on sequence analysis, while the two helices correspond to the central (CR1) and C-terminal (CR2) conserved regions, respectively. The structure of the MG438 subunit presents an overall cyclic topology with an intramolecular 2-fold axis that superimposes the N and the C-half parts, each half containing a globular domain and a conserved helix. TRDs are found to be structurally related with the small domain of the Type II N6-adenine DNA MTase TaqI. These relationships together with the structural peculiarities of MG438, in particular the presence of the intramolecular quasi-symmetry, allow the proposal of a model for S subunits recognition of their DNA targets in agreement with previous experimental results. In the crystal, two subunits of MG438 related by a crystallographic 2-fold axis present a large contact area mainly involving the symmetric interactions of a cluster of exposed hydrophobic residues. Comparison with the recently reported structure of an S subunit from the archaea Methanococcus jannaschii highlights the structural features preserved despite a sequence identity below 20%, but also reveals important differences in the globular domains and in their disposition with respect to the conserved regions. |
==About this Structure== | ==About this Structure== | ||
| - | 1YDX is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Mycoplasma_genitalium Mycoplasma genitalium] with CL as [http://en.wikipedia.org/wiki/ligand ligand]. Full crystallographic information is available from [http:// | + | 1YDX is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Mycoplasma_genitalium Mycoplasma genitalium] with <scene name='pdbligand=CL:'>CL</scene> as [http://en.wikipedia.org/wiki/ligand ligand]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1YDX OCA]. |
==Reference== | ==Reference== | ||
| Line 22: | Line 22: | ||
[[Category: type-i hsds]] | [[Category: type-i hsds]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 16:04:20 2008'' |
Revision as of 14:04, 21 February 2008
|
Crystal structure of Type-I restriction-modification system S subunit from M. genitalium
Overview
The crystal structure of the eubacteria Mycoplasma genitalium ORF MG438 polypeptide, determined by multiple anomalous dispersion and refined at 2.3 A resolution, reveals the organization of S subunits from the Type I restriction and modification system. The structure consists of two globular domains, with about 150 residues each, separated by a pair of 40 residue long antiparallel alpha-helices. The globular domains correspond to the variable target recognition domains (TRDs), as previously defined for S subunits on sequence analysis, while the two helices correspond to the central (CR1) and C-terminal (CR2) conserved regions, respectively. The structure of the MG438 subunit presents an overall cyclic topology with an intramolecular 2-fold axis that superimposes the N and the C-half parts, each half containing a globular domain and a conserved helix. TRDs are found to be structurally related with the small domain of the Type II N6-adenine DNA MTase TaqI. These relationships together with the structural peculiarities of MG438, in particular the presence of the intramolecular quasi-symmetry, allow the proposal of a model for S subunits recognition of their DNA targets in agreement with previous experimental results. In the crystal, two subunits of MG438 related by a crystallographic 2-fold axis present a large contact area mainly involving the symmetric interactions of a cluster of exposed hydrophobic residues. Comparison with the recently reported structure of an S subunit from the archaea Methanococcus jannaschii highlights the structural features preserved despite a sequence identity below 20%, but also reveals important differences in the globular domains and in their disposition with respect to the conserved regions.
About this Structure
1YDX is a Single protein structure of sequence from Mycoplasma genitalium with as ligand. Full crystallographic information is available from OCA.
Reference
Crystal structure of a putative type I restriction-modification S subunit from Mycoplasma genitalium., Calisto BM, Pich OQ, Pinol J, Fita I, Querol E, Carpena X, J Mol Biol. 2005 Aug 26;351(4):749-62. PMID:16038930
Page seeded by OCA on Thu Feb 21 16:04:20 2008
