Crystal structure of GyrA intein from Mycobacterium xenopi reveals structural basis of protein splicing

Thomas Klabunde, Sujata Sharma, Amalio Telenti, William R. Jacobs, James C. Sacchettini

Research output: Contribution to journalArticle

190 Scopus citations

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 β-fold with the catalytic splice junctions at the ends of two adjacent antiparallel β- 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.

Original languageEnglish (US)
Pages (from-to)31-36
Number of pages6
JournalNature structural biology
Volume5
Issue number1
DOIs
StatePublished - Feb 5 1998

ASJC Scopus subject areas

  • Structural Biology
  • Biochemistry
  • Genetics

Fingerprint Dive into the research topics of 'Crystal structure of GyrA intein from Mycobacterium xenopi reveals structural basis of protein splicing'. Together they form a unique fingerprint.

  • Cite this