1A73

INTRON-ENCODED ENDONUCLEASE I-PPOI COMPLEXED WITH DNA

Summary for 1A73

• Entry DOI: 10.2210/pdb1a73/pdb
• Descriptor: DNA (5'-D(*TP*TP*GP*AP*CP*TP*CP*TP*CP*TP*TP*AP*A)-3'), DNA (5'-D(P*GP*AP*GP*AP*GP*TP*CP*A)-3'), INTRON 3 (I-PPO) ENCODED ENDONUCLEASE, ... (6 entities in total)
• Functional Keywords: complex (homing endonuclease-dna), intron, zinc, dna binding, protein folding, hydrolase-dna complex, hydrolase/dna
• Biological source: Physarum polycephalum
• Total number of polymer chains: 6
• Total formula weight: 48717.18

Authors

Flick, K.E.,Monnat Junior, R.J.,Stoddard, B.L. (deposition date: 1998-03-19, release date: 1998-10-14, Last modification date: 2024-02-07)

Primary citation

Flick, K.E.,Jurica, M.S.,Monnat Jr., R.J.,Stoddard, B.L.
DNA binding and cleavage by the nuclear intron-encoded homing endonuclease I-PpoI.
Nature, 394:96-101, 1998

PubMed Abstract: Homing endonucleases are a diverse collection of proteins that are encoded by genes with mobile, self-splicing introns. They have also been identified in self-splicing inteins (protein introns). These enzymes promote the movement of the DNA sequences that encode them from one chromosome location to another; they do this by making a site-specific double-strand break at a target site in an allele that lacks the corresponding mobile intron. The target sites recognized by these small endonucleases are generally long (14-44 base pairs). Four families of homing endonucleases have been identified, including the LAGLIDADG, the His-Cys box, the GIY-YIG and the H-N-H endonucleases. The first identified His-Cys box homing endonuclease was I-PpoI from the slime mould Physarum polycephalum. Its gene resides in one of only a few nuclear introns known to exhibit genetic mobility. Here we report the structure of the I-PpoI homing endonuclease bound to homing-site DNA determined to 1.8 A resolution. I-PpoI displays an elongated fold of dimensions 25 x 35 x 80 A, with mixed alpha/beta topology. Each I-PpoI monomer contains three antiparallel beta-sheets flanked by two long alpha-helices and a long carboxy-terminal tail, and is stabilized by two bound zinc ions 15 A apart. The enzyme possesses a new zinc-bound fold and endonuclease active site. The structure has been determined in both uncleaved substrate and cleaved product complexes.

PubMed: 9665136
DOI: 10.1038/27952

Experimental method

X-RAY DIFFRACTION (1.8 Å)