Purification and crystallization of precursors and autoprocessed enzymes of Flavobacterium glycosylasparaginase: an N-terminal nucleophile hydrolase

Glycosylasparaginase (GA) represents a novel group of proteins that are activated by self-catalyzed peptide-bond cleavage from a single-chain precursor to yield the two subunits required for hydrolase activity. The wild-type GA precursor autoproteolyzes spontaneously into α and β subunits. Strategies are reported here for purification to homogeneity of GA from Flavobacterium meningosepticum in both single-chain precursor and mature (autoprocessed) forms. The recombinant proteins crystallize in different space groups: P1 and P2₁ for the precursor and mature enzymes, respectively. The precursor crystals diffract to 1.9 Å resolution with laboratory X-ray radiation.