1am2: Difference between revisions
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'''GYRA INTEIN FROM MYCOBACTERIUM XENOPI''' | '''GYRA INTEIN FROM MYCOBACTERIUM XENOPI''' | ||
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[[Category: Sacchettini, J C.]] | [[Category: Sacchettini, J C.]] | ||
[[Category: Sharma, S.]] | [[Category: Sharma, S.]] | ||
[[Category: | [[Category: Intein]] | ||
[[Category: | [[Category: Protein splicing]] | ||
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Revision as of 10:26, 2 May 2008
GYRA INTEIN FROM MYCOBACTERIUM XENOPI
OverviewOverview
Several genes from prokaryotes and lower eukaryotes have been found to contain an in-frame open reading frame, which encodes for an internal protein (intein). Post-translationally, the internal polypeptide auto-splices and ligates the external sequences to yield a functional external protein (extein) and an intein. Most, but not all inteins, contain, apart from a splicing domain, a separate endonucleolytic domain that enables them to maintain their presence by a homing mechanism. We report here the crystal structure of an intein found in the gyrase A subunit from Mycobacterium xenopi at 2.2 A resolution. The structure contains an unusual beta-fold with the catalytic splice junctions at the ends of two adjacent antiparallel beta-strands. The arrangement of the active site residues Ser 1, Thr 72, His 75, His 197, and Asn 198 is consistent with a four-step mechanism for the cleavage-ligation reaction. Using site-directed mutagenesis, the N-terminal cysteine, proposed as the nucleophile in the first step of the splicing reaction, was changed to a Ser 1 and Ala 0, thus capturing the intein in a pre-spliced state.
About this StructureAbout this Structure
1AM2 is a Single protein structure of sequence from Mycobacterium xenopi. Full crystallographic information is available from OCA.
ReferenceReference
Crystal structure of GyrA intein from Mycobacterium xenopi reveals structural basis of protein splicing., Klabunde T, Sharma S, Telenti A, Jacobs WR Jr, Sacchettini JC, Nat Struct Biol. 1998 Jan;5(1):31-6. PMID:9437427 Page seeded by OCA on Fri May 2 10:26:15 2008