InterPro

GA-binding protein alpha is a transcription factor capable of interacting with purine rich repeats (GA repeats). This N-terminal domain found in the transcription factor GABP alpha consists of a five-stranded beta-sheet crossed by a distorted helix and has been termed OST domain. The surface of the GABP alpha OST domain contains two clusters of negatively-charged residues suggesting there are positively-charged partner proteins. The OST domain binds to the CH1 and CH3 domains of the co-activator histone acetyltransferase CBP/p300 [PMID: 18295234].