2OLG

Crystal structure of the serine protease domain of prophenoloxidase activating factor-I in a zymogen form

Summary for 2OLG

• Entry DOI: 10.2210/pdb2olg/pdb
• Related: 2B9L
• Descriptor: Pro-phenoloxidase activating enzyme-I, 2-acetamido-2-deoxy-beta-D-glucopyranose, SULFATE ION, ... (5 entities in total)
• Functional Keywords: prophenoloxidase activating factor-i, ppaf-i, serine protease, hydrolase
• Biological source: Holotrichia diomphalia
• Total number of polymer chains: 1
• Total formula weight: 30957.82

Authors

Ha, N.C.,Piao, S. (deposition date: 2007-01-19, release date: 2007-02-06, Last modification date: 2024-11-20)

Primary citation

Piao, S.,Kim, S.,Kim, J.H.,Park, J.W.,Lee, B.L.,Ha, N.C.
Crystal structure of the serine protease domain of prophenoloxidase activating factor-I
J.Biol.Chem., 282:10783-10791, 2007

PubMed Abstract: A family of serine proteases (SPs) mediates the proteolytic cascades of embryonic development and immune response in invertebrates. These proteases, called easter-type SPs, consist of clip and chymotrypsin-like SP domains. The SP domain of easter-type proteases differs from those of typical SPs in its primary structure. Herein, we report the first crystal structure of the SP domain of easter-type proteases, presented as that of prophenoloxidase activating factor (PPAF)-I in zymogen form. This structure reveals several important structural features including a bound calcium ion, an additional loop with a unique disulfide linkage, a canyon-like deep active site, and an exposed activation loop. We subsequently show the role of the bound calcium and the proteolytic susceptibility of the activation loop, which occurs in a clip domain-independent manner. Based on biochemical study in the presence of heparin, we suggest that PPAF-III, highly homologous to PPAF-I, contains a surface patch that is responsible for enhancing the catalytic activity through interaction with a nonsubstrate region of a target protein. These results provide insights into an activation mechanism of easter-type proteases in proteolytic cascades, in comparison with the well studied blood coagulation enzymes in mammals.

PubMed: 17287215
DOI: 10.1074/jbc.M611556200

Experimental method

X-RAY DIFFRACTION (1.7 Å)