2B9L

Crystal structure of prophenoloxidase activating factor-II from the beetle Holotrichia diomphalia

Summary for 2B9L

• Entry DOI: 10.2210/pdb2b9l/pdb
• Descriptor: prophenoloxidase activating factor, alpha-L-fucopyranose-(1-3)-[2-acetamido-2-deoxy-beta-D-glucopyranose-(1-4)][alpha-L-fucopyranose-(1-6)]2-acetamido-2-deoxy-beta-D-glucopyranose, SULFATE ION, ... (5 entities in total)
• Functional Keywords: clip domain, easter, innate immunity, melanin, immune system-protein binding complex, immune system/protein binding
• Biological source: Holotrichia diomphalia
• Total number of polymer chains: 1
• Total formula weight: 44382.87

Authors

Piao, S.,Song, Y.-L.,Park, S.Y.,Lee, B.L.,Oh, B.-H.,Ha, N.-C. (deposition date: 2005-10-12, release date: 2006-01-03, Last modification date: 2024-10-30)

Primary citation

Piao, S.,Song, Y.L.,Kim, J.H.,Park, S.Y.,Park, J.W.,Lee, B.L.,Oh, B.H.,Ha, N.C.
Crystal structure of a clip-domain serine protease and functional roles of the clip domains.
Embo J., 24:4404-4414, 2005

PubMed Abstract: Clip-domain serine proteases (SPs) are the essential components of extracellular signaling cascades in various biological processes, especially in embryonic development and the innate immune responses of invertebrates. They consist of a chymotrypsin-like SP domain and one or two clip domains at the N-terminus. Prophenoloxidase-activating factor (PPAF)-II, which belongs to the noncatalytic clip-domain SP family, is indispensable for the generation of the active phenoloxidase leading to melanization, a major defense mechanism of insects. Here, the crystal structure of PPAF-II reveals that the clip domain adopts a novel fold containing a central cleft, which is distinct from the structures of defensins with a similar arrangement of cysteine residues. Ensuing studies demonstrated that PPAF-II forms a homo-oligomer upon cleavage by the upstream protease and that the clip domain of PPAF-II functions as a module for binding phenoloxidase through the central cleft, while the clip domain of a catalytically active easter-type SP plays an essential role in the rapid activation of its protease domain.

PubMed: 16362048
DOI: 10.1038/sj.emboj.7600891

Experimental method

X-RAY DIFFRACTION (2 Å)