1mi8
From Proteopedia
(New page: 200px<br /><applet load="1mi8" size="450" color="white" frame="true" align="right" spinBox="true" caption="1mi8, resolution 2.0Å" /> '''2.0 Angstrom crystal ...) |
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| - | [[Image:1mi8.gif|left|200px]]<br /><applet load="1mi8" size=" | + | [[Image:1mi8.gif|left|200px]]<br /><applet load="1mi8" size="350" color="white" frame="true" align="right" spinBox="true" |
caption="1mi8, resolution 2.0Å" /> | caption="1mi8, resolution 2.0Å" /> | ||
'''2.0 Angstrom crystal structure of a DnaB intein from Synechocystis sp. PCC 6803'''<br /> | '''2.0 Angstrom crystal structure of a DnaB intein from Synechocystis sp. PCC 6803'''<br /> | ||
==Overview== | ==Overview== | ||
| - | We have determined the crystal structure of a 154-residue intein derived | + | We have determined the crystal structure of a 154-residue intein derived from the dnaB gene of Synechocystis sp. strain PCC6803 and refined it to a 2.0-A resolution. The x-ray structure suggests that this intein possesses two catalytic sites that appear to be separately responsible for splicing and cleavage of the N- and C-terminal scissile bonds. The conserved intein block F residues are the important components of a catalytic site for side chain cyclization of the last intein residue, Asn-154. The data suggest that the imidazole ring of His-143 is involved in the activation of the side chain Ndelta atom of Asn-154, leading to a nucleophilic attack on the carbonyl carbon of Asn-154. Substitution of His-143 with Ala or Gln resulted in the inhibition of C-terminal cleavage. His-153, Asp-136, and a water molecule appear to constitute an oxyanion binding site by contacting the carbonyl oxygen of Asn-154 to stabilize the transition state. The structure and mutagenesis data also support that the close contact between the hydroxyl groups of Thr-138 and Ser-155, whose side chain participates in an S --> O acyl shift, plays an important role in the nucleophile orientation. Our structural modeling suggests that this catalytic module is conserved in the C-terminal subdomains of inteins from diverse organisms. |
==About this Structure== | ==About this Structure== | ||
| - | 1MI8 is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Synechocystis_sp. Synechocystis sp.]. Full crystallographic information is available from [http:// | + | 1MI8 is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Synechocystis_sp. Synechocystis sp.]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1MI8 OCA]. |
==Reference== | ==Reference== | ||
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[[Category: all beta-strands]] | [[Category: all beta-strands]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 13:55:26 2008'' |
Revision as of 11:55, 21 February 2008
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2.0 Angstrom crystal structure of a DnaB intein from Synechocystis sp. PCC 6803
Overview
We have determined the crystal structure of a 154-residue intein derived from the dnaB gene of Synechocystis sp. strain PCC6803 and refined it to a 2.0-A resolution. The x-ray structure suggests that this intein possesses two catalytic sites that appear to be separately responsible for splicing and cleavage of the N- and C-terminal scissile bonds. The conserved intein block F residues are the important components of a catalytic site for side chain cyclization of the last intein residue, Asn-154. The data suggest that the imidazole ring of His-143 is involved in the activation of the side chain Ndelta atom of Asn-154, leading to a nucleophilic attack on the carbonyl carbon of Asn-154. Substitution of His-143 with Ala or Gln resulted in the inhibition of C-terminal cleavage. His-153, Asp-136, and a water molecule appear to constitute an oxyanion binding site by contacting the carbonyl oxygen of Asn-154 to stabilize the transition state. The structure and mutagenesis data also support that the close contact between the hydroxyl groups of Thr-138 and Ser-155, whose side chain participates in an S --> O acyl shift, plays an important role in the nucleophile orientation. Our structural modeling suggests that this catalytic module is conserved in the C-terminal subdomains of inteins from diverse organisms.
About this Structure
1MI8 is a Single protein structure of sequence from Synechocystis sp.. Full crystallographic information is available from OCA.
Reference
Crystal structure of a mini-intein reveals a conserved catalytic module involved in side chain cyclization of asparagine during protein splicing., Ding Y, Xu MQ, Ghosh I, Chen X, Ferrandon S, Lesage G, Rao Z, J Biol Chem. 2003 Oct 3;278(40):39133-42. Epub 2003 Jul 23. PMID:12878593
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