1AM2

GYRA INTEIN FROM MYCOBACTERIUM XENOPI

Summary for 1AM2

• Entry DOI: 10.2210/pdb1am2/pdb
• Descriptor: MXE GYRA INTEIN (2 entities in total)
• Functional Keywords: intein, protein splicing
• Biological source: Mycobacterium xenopi
• Cellular location: Cytoplasm (Potential): P72065
• Total number of polymer chains: 1
• Total formula weight: 21364.07

Authors

Klabunde, T.,Sharma, S.,Sacchettini, J.C. (deposition date: 1997-06-20, release date: 1998-06-24, Last modification date: 2024-02-07)

Primary citation

Klabunde, T.,Sharma, S.,Telenti, A.,Jacobs Jr., W.R.,Sacchettini, J.C.
Crystal structure of GyrA intein from Mycobacterium xenopi reveals structural basis of protein splicing.
Nat.Struct.Biol., 5:31-36, 1998

PubMed Abstract: 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.

PubMed: 9437427
DOI: 10.1038/nsb0198-31

Experimental method

X-RAY DIFFRACTION (2.2 Å)