4R9I

Crystal structure of cysteine proteinase inhibitor Serpin18 from Bombyx mori

Summary for 4R9I

• Entry DOI: 10.2210/pdb4r9i/pdb
• Descriptor: Serpin-18, SODIUM ION, CITRATE ANION, ... (5 entities in total)
• Functional Keywords: proteinase inhibitor, hydrolase inhibitor
• Biological source: Bombyx mori (silkworm)
• Total number of polymer chains: 1
• Total formula weight: 43194.65

Authors

Guo, P.C.,He, H.W.,Zhao, P.,Xia, Q.Y. (deposition date: 2014-09-05, release date: 2015-09-09, Last modification date: 2024-03-20)

Primary citation

Guo, P.C.,Dong, Z.,Zhao, P.,Zhang, Y.,He, H.W.,Tan, X.,Zhang, W.,Xia, Q.Y.
Structural insights into the unique inhibitory mechanism of the silkworm protease inhibitor serpin18
Sci Rep, 5:11863-11863, 2015

PubMed Abstract: Serpins generally serve as inhibitors that utilize a mobile reactive center loop (RCL) as bait to trap protease targets. Here, we present the crystal structure of serpin18 from Bombyx mori at 1.65 Å resolution, which has a very short and stable RCL. Activity analysis showed that the inhibitory target of serpin18 is a cysteine protease rather than a serine protease. Notably, this inhibitiory reaction results from the formation of an intermediate complex, which then follows for the digestion of protease and inhibitor into small fragments. This activity differs from previously reported modes of inhibition for serpins. Our findings have thus provided novel structural insights into the unique inhibitory mechanism of serpin18. Furthermore, one physiological target of serpin18, fibroinase, was identified, which enables us to better define the potential role for serpin18 in regulating fibroinase activity during B. mori development.

PubMed: 26148664
DOI: 10.1038/srep11863

Experimental method

X-RAY DIFFRACTION (1.65 Å)