Aberrant functioning of serine proteases in inflammatory and carcinogenic processes within the gastrointestinal tract(GIT)has prompted scientists to investigate the potential of serine protease inhibitors,both natural...Aberrant functioning of serine proteases in inflammatory and carcinogenic processes within the gastrointestinal tract(GIT)has prompted scientists to investigate the potential of serine protease inhibitors,both natural and synthetic,as modulators of their proteolytic activities.Protease inhibitors of the Bowman-Birk type,a major protease inhibitor family in legume seeds,which inhibit potently and specifically trypsin-and chymotrypsin-like proteases,are currently being investigated as colorectal chemopreventive agents.Physiologically relevant amounts of Bowman-Birk inhibitors(BBI)can reach the large intestine in active form due to their extraordinary resistance to extreme conditions within the GIT.Studies in animal models have proven that dietary BBI from several legume sources,including soybean,pea,lentil and chickpea,can prevent or suppress carcinogenic and inflammatory processes within the GIT.Although the therapeutic targets and the action mechanism of BBI have not yet been elucidated,the emerging evidence suggests that BBI exert their preventive properties via protease inhibition;in this sense,serine proteases should be considered as primary targets in early stages of carcinogenesis.The validation of candidate serine proteases as therapeutic targets together with the identification,within the wide array of natural BBI variants,of the most potent and specific protease inhibitors,are necessary to better understand the potential of this protein family as colorectal chemopreventive agents.展开更多
Trypsin inhibitors have been found in various animals, plants and microorganisms.There were two types of trypsin inhibitors in soybean including Bowman-Birk protease inhibitors(BBI) and Kunitz in-hibitors(KTI).The dif...Trypsin inhibitors have been found in various animals, plants and microorganisms.There were two types of trypsin inhibitors in soybean including Bowman-Birk protease inhibitors(BBI) and Kunitz in-hibitors(KTI).The different BBI genes from wild soybean(G.soja) and cultivated soybean(G.max) formed a multigene family.We constructed a cDNA library of cultivar 'SuiNong 14' seed at the R7 growth stage using the SMART Kit.Seventeen contigs or singletons were highly homologous to soy-bean protease inhibitors.Contigs of 5, 35, 8 and 9 were highly homologous to BBI family members BBI-A1, BBI-A2, BBI-C and BBI-D, respectively.Sequence analyses showed there were novel allelic varia-tions among the 4 BBI members in SuiNong 14.Based on the comparison of soybean seed cDNA li-braries from different developmental stages, it was apparent that the expression of trypsin inhibitors increased during seed development in soybean.Phylogenetic analysis of BBI gene sequences among dicotyledonous and monocotyledonous plants demonstrated that these genes shared a common pro-genitor.展开更多
The WIP1-2 gene was cloned from rice. It be-longs to the Bowman-Birk inhibitor gene family. Northern blot showed that expression of this gene was induced by wounding and jasmonic acid (JA). It indicates that the OsWIP...The WIP1-2 gene was cloned from rice. It be-longs to the Bowman-Birk inhibitor gene family. Northern blot showed that expression of this gene was induced by wounding and jasmonic acid (JA). It indicates that the OsWIP1 gene plays an important role in the rice defense sys-tem. The OsWIP1-2 was cloned into pET28a and expressed in E. coli. Its expressed product was purified in the form of fusion protein and tested for the inhibitory activities against trypsin and chymotrypsin. It was found that the fusion pro-tein could inhibit chymotrypsin, but not trypsin. It was also found that the His tag at its C-terminal affected its inhibitory activity significantly. The fusion protein with a natural C-terminal had the inhibitory activity, while no inhibitory activity was detected in the fusion protein with a (His)6-tag at its C-terminal. This implies that extra amino acid residues at the C-terminal of OsWIP1-2 may interfere with its correct folding. The inhibitory assay indicated that the members of rice Bowman-Birk inhibitor gene family probably differenti-ated both in their structure and function.展开更多
Rice Bowman-Birk inhibitors (RBBI), with one (8 kD) or two homologous domains (16 kD), were found to be effective trypsin inhibitors in vitro. In this study, we demonstrate that the 25-kD protein corresponding to the ...Rice Bowman-Birk inhibitors (RBBI), with one (8 kD) or two homologous domains (16 kD), were found to be effective trypsin inhibitors in vitro. In this study, we demonstrate that the 25-kD protein corresponding to the three-domain RBBI indeed ex- ists in rice in planta, and that the RBBIs are regulated by development and wounding. We also found by inhibitory activity assay that the 3:13 disulfide bond, but not the 4:5 disulfide bond, suppresses the tryp- sin-inhibitory activity, and the D3 domain of RBBI3-1 has no inhibitory activity against trypsin, chymotryp- sin, paparin or subtilisin. Mutation analyses showed that conversion from Lys to Leu or Tyr in the N-terminal P1 site in D1 domain did not create chy- motrypsin-inhibitory activity, suggesting that the structure of the reactive loop in D1 domain hinder the new inhibitory specificity at P1 site, and the chy- motrypsin-inhibitory activity might need the participa- tion of other structures, e.g. 3:13 disulfide bond.展开更多
基金Supported by ERDF-co-financed grant from the Spanish CICYT,No.AGL2011-26353 to Clemente AClemente A involved in COST Action FA1005 INFOGEST on Food Digestion
文摘Aberrant functioning of serine proteases in inflammatory and carcinogenic processes within the gastrointestinal tract(GIT)has prompted scientists to investigate the potential of serine protease inhibitors,both natural and synthetic,as modulators of their proteolytic activities.Protease inhibitors of the Bowman-Birk type,a major protease inhibitor family in legume seeds,which inhibit potently and specifically trypsin-and chymotrypsin-like proteases,are currently being investigated as colorectal chemopreventive agents.Physiologically relevant amounts of Bowman-Birk inhibitors(BBI)can reach the large intestine in active form due to their extraordinary resistance to extreme conditions within the GIT.Studies in animal models have proven that dietary BBI from several legume sources,including soybean,pea,lentil and chickpea,can prevent or suppress carcinogenic and inflammatory processes within the GIT.Although the therapeutic targets and the action mechanism of BBI have not yet been elucidated,the emerging evidence suggests that BBI exert their preventive properties via protease inhibition;in this sense,serine proteases should be considered as primary targets in early stages of carcinogenesis.The validation of candidate serine proteases as therapeutic targets together with the identification,within the wide array of natural BBI variants,of the most potent and specific protease inhibitors,are necessary to better understand the potential of this protein family as colorectal chemopreventive agents.
基金the "863" Project of National High Technology Research and Devel-opment Program of China (Grant No. 2006AA100104 and 2006AA10A110)Na-tional Natural Science Foundation of China (Grant No. 30490251)+1 种基金National Key Technologies R&D Program in the 11th Five-Year Plan (Grant No. 2006BAD13B05)Basic Research Funding of the Institute of Crop Science
文摘Trypsin inhibitors have been found in various animals, plants and microorganisms.There were two types of trypsin inhibitors in soybean including Bowman-Birk protease inhibitors(BBI) and Kunitz in-hibitors(KTI).The different BBI genes from wild soybean(G.soja) and cultivated soybean(G.max) formed a multigene family.We constructed a cDNA library of cultivar 'SuiNong 14' seed at the R7 growth stage using the SMART Kit.Seventeen contigs or singletons were highly homologous to soy-bean protease inhibitors.Contigs of 5, 35, 8 and 9 were highly homologous to BBI family members BBI-A1, BBI-A2, BBI-C and BBI-D, respectively.Sequence analyses showed there were novel allelic varia-tions among the 4 BBI members in SuiNong 14.Based on the comparison of soybean seed cDNA li-braries from different developmental stages, it was apparent that the expression of trypsin inhibitors increased during seed development in soybean.Phylogenetic analysis of BBI gene sequences among dicotyledonous and monocotyledonous plants demonstrated that these genes shared a common pro-genitor.
文摘The WIP1-2 gene was cloned from rice. It be-longs to the Bowman-Birk inhibitor gene family. Northern blot showed that expression of this gene was induced by wounding and jasmonic acid (JA). It indicates that the OsWIP1 gene plays an important role in the rice defense sys-tem. The OsWIP1-2 was cloned into pET28a and expressed in E. coli. Its expressed product was purified in the form of fusion protein and tested for the inhibitory activities against trypsin and chymotrypsin. It was found that the fusion pro-tein could inhibit chymotrypsin, but not trypsin. It was also found that the His tag at its C-terminal affected its inhibitory activity significantly. The fusion protein with a natural C-terminal had the inhibitory activity, while no inhibitory activity was detected in the fusion protein with a (His)6-tag at its C-terminal. This implies that extra amino acid residues at the C-terminal of OsWIP1-2 may interfere with its correct folding. The inhibitory assay indicated that the members of rice Bowman-Birk inhibitor gene family probably differenti-ated both in their structure and function.
文摘Rice Bowman-Birk inhibitors (RBBI), with one (8 kD) or two homologous domains (16 kD), were found to be effective trypsin inhibitors in vitro. In this study, we demonstrate that the 25-kD protein corresponding to the three-domain RBBI indeed ex- ists in rice in planta, and that the RBBIs are regulated by development and wounding. We also found by inhibitory activity assay that the 3:13 disulfide bond, but not the 4:5 disulfide bond, suppresses the tryp- sin-inhibitory activity, and the D3 domain of RBBI3-1 has no inhibitory activity against trypsin, chymotryp- sin, paparin or subtilisin. Mutation analyses showed that conversion from Lys to Leu or Tyr in the N-terminal P1 site in D1 domain did not create chy- motrypsin-inhibitory activity, suggesting that the structure of the reactive loop in D1 domain hinder the new inhibitory specificity at P1 site, and the chy- motrypsin-inhibitory activity might need the participa- tion of other structures, e.g. 3:13 disulfide bond.
