Site-specific endonuclease AbaI from Azospirillum brasilense UQ 1796 is an isoschizomer of endonuclease BclI.

: The site-specific endonuclease AbaI was isolated and purified to functional purity from the soil nitrogen-fixing bacterium Azospirillum brasilense UQ 1796. Purification included successive chromatography on columns with phosphocellulose, heparin-Sepharose, and hydroxyapatite. The purified enzyme recognizes the palindromic DNA sequence 5'-T decreases ATCA-3' and cleaves it as shown by the arrow. The isolated enzyme belongs to class II restriction endonuclease and is an isoschizomer of endonuclease BclI. The enzyme of AbaI is active at 26-56 degrees C. The optimal temperature is 48 degrees C and the optimal buffer is LRB.