PubMed:24901510 JSONTXT

{"target":"https://pubannotation.org/docs/sourcedb/PubMed/sourceid/24901510","sourcedb":"PubMed","sourceid":"24901510","source_url":"https://www.ncbi.nlm.nih.gov/pubmed/24901510","text":"Structure-function relationship of SW-AT-1, a serpin-type protease inhibitor in silkworm.\nAlthough SW-AT-1, a serpin-type trypsin inhibitor from silkworm (Bombyx mori), was identified in previous study, its structure-function relationship has not been studied. In this study, SW-AT-1 was cloned from the body wall of silkworm and expressed in E. coli. rSW-AT-1 inhibited both trypsin and chymotrypsin in a concentration-dependent manner. The association rate constant for rSW-AT-1 and trypsin is 1.31×10-5 M-1s-1, for rSW-AT-1 and chymotrpsin is 2.85×10-6 M-1s-1. Circular dichroism (CD) assay showed 33% α-helices, 16% β-sheets, 17% turns, and 31% random coils in the secondary structure of the protein. Enzymatic and CD analysis indicated that rSW-AT-1 was stable at wide pH range between 4-10, and exhibited the highest activity at weakly acidic or alkaline condition. The predicted three-dimensional structure of SW-AT-1 by PyMOL (v1.4) revealed a deductive reactive centre loop (RCL) near the C-terminus, which was extended from the body of the molecule. In addition to trypsin cleavage site in RCL, matrix-assisted laser desorption ionization time of flight mass spectrometry indicated that the chymotrypsin cleavage site of SW-AT-1 was between F336 and T337 in RCL. Directed mutagenesis indicated that both the N- and C-terminal sides of RCL have effects on the activity, and G327 and E329 played an important role in the proper folding of RCL. The physiological role of SW-AT-1 in the defense responses of silkworm were also discussed.","tracks":[{"project":"Allie","denotations":[{"id":"SS1_24901510_4_0","span":{"begin":564,"end":582},"obj":"expanded"},{"id":"SS2_24901510_4_0","span":{"begin":584,"end":586},"obj":"abbr"},{"id":"SS1_24901510_6_0","span":{"begin":962,"end":982},"obj":"expanded"},{"id":"SS2_24901510_6_0","span":{"begin":984,"end":987},"obj":"abbr"}],"relations":[{"id":"AE1_24901510_4_0","pred":"abbreviatedTo","subj":"SS1_24901510_4_0","obj":"SS2_24901510_4_0"},{"id":"AE1_24901510_6_0","pred":"abbreviatedTo","subj":"SS1_24901510_6_0","obj":"SS2_24901510_6_0"}],"attributes":[{"subj":"SS1_24901510_4_0","pred":"source","obj":"Allie"},{"subj":"SS2_24901510_4_0","pred":"source","obj":"Allie"},{"subj":"SS1_24901510_6_0","pred":"source","obj":"Allie"},{"subj":"SS2_24901510_6_0","pred":"source","obj":"Allie"}]},{"project":"silkworm","denotations":[{"id":"T1","span":{"begin":80,"end":88},"obj":"Species:7091"},{"id":"T2","span":{"begin":145,"end":153},"obj":"Species:7091"},{"id":"T3","span":{"begin":155,"end":166},"obj":"Species:7091"},{"id":"T4","span":{"begin":317,"end":325},"obj":"Species:7091"},{"id":"T5","span":{"begin":343,"end":350},"obj":"Species:562"},{"id":"T6","span":{"begin":493,"end":497},"obj":"Species:1433131"},{"id":"T7","span":{"begin":543,"end":547},"obj":"Species:1433131"},{"id":"T8","span":{"begin":1514,"end":1522},"obj":"Species:7091"}],"attributes":[{"subj":"T1","pred":"source","obj":"silkworm"},{"subj":"T2","pred":"source","obj":"silkworm"},{"subj":"T3","pred":"source","obj":"silkworm"},{"subj":"T4","pred":"source","obj":"silkworm"},{"subj":"T5","pred":"source","obj":"silkworm"},{"subj":"T6","pred":"source","obj":"silkworm"},{"subj":"T7","pred":"source","obj":"silkworm"},{"subj":"T8","pred":"source","obj":"silkworm"}]},{"project":"silkwormbase","denotations":[{"id":"T1","span":{"begin":80,"end":88},"obj":"Species:7091"},{"id":"T2","span":{"begin":145,"end":153},"obj":"Species:7091"},{"id":"T3","span":{"begin":155,"end":166},"obj":"Species:7091"},{"id":"T4","span":{"begin":317,"end":325},"obj":"Species:7091"},{"id":"T5","span":{"begin":343,"end":350},"obj":"Species:562"},{"id":"T6","span":{"begin":493,"end":497},"obj":"Species:1433131"},{"id":"T7","span":{"begin":543,"end":547},"obj":"Species:1433131"},{"id":"T8","span":{"begin":1514,"end":1522},"obj":"Species:7091"}],"attributes":[{"subj":"T1","pred":"source","obj":"silkwormbase"},{"subj":"T2","pred":"source","obj":"silkwormbase"},{"subj":"T3","pred":"source","obj":"silkwormbase"},{"subj":"T4","pred":"source","obj":"silkwormbase"},{"subj":"T5","pred":"source","obj":"silkwormbase"},{"subj":"T6","pred":"source","obj":"silkwormbase"},{"subj":"T7","pred":"source","obj":"silkwormbase"},{"subj":"T8","pred":"source","obj":"silkwormbase"}]},{"project":"silkworm_phenotype","denotations":[{"id":"T8","span":{"begin":1514,"end":1522},"obj":"Species:7091"},{"id":"T7","span":{"begin":543,"end":547},"obj":"Species:1433131"},{"id":"T6","span":{"begin":493,"end":497},"obj":"Species:1433131"},{"id":"T5","span":{"begin":343,"end":350},"obj":"Species:562"},{"id":"T4","span":{"begin":317,"end":325},"obj":"Species:7091"},{"id":"T3","span":{"begin":155,"end":166},"obj":"Species:7091"},{"id":"T2","span":{"begin":145,"end":153},"obj":"Species:7091"},{"id":"T1","span":{"begin":80,"end":88},"obj":"Species:7091"}],"attributes":[{"subj":"T8","pred":"source","obj":"silkworm_phenotype"},{"subj":"T7","pred":"source","obj":"silkworm_phenotype"},{"subj":"T6","pred":"source","obj":"silkworm_phenotype"},{"subj":"T5","pred":"source","obj":"silkworm_phenotype"},{"subj":"T4","pred":"source","obj":"silkworm_phenotype"},{"subj":"T3","pred":"source","obj":"silkworm_phenotype"},{"subj":"T2","pred":"source","obj":"silkworm_phenotype"},{"subj":"T1","pred":"source","obj":"silkworm_phenotype"}]}],"config":{"attribute types":[{"pred":"source","value type":"selection","values":[{"id":"Allie","color":"#ecda93","default":true},{"id":"silkworm","color":"#c093ec"},{"id":"silkwormbase","color":"#93eca6"},{"id":"silkworm_phenotype","color":"#ec9399"}]}]}}