The spike protein(S)of SARS-CoV-2 is responsible for viral attachment and entry,thus a major factor for host suscep-tibility,tissue tropism,virulence and pathogenicity.The S is divided with S1 and S2 region,and the S1...The spike protein(S)of SARS-CoV-2 is responsible for viral attachment and entry,thus a major factor for host suscep-tibility,tissue tropism,virulence and pathogenicity.The S is divided with S1 and S2 region,and the S1 contains the receptor-binding domain(RBD),while the S2 contains the hydrophobic fusion domain for the entry into the host cell.Numerous host proteases have been implicated in the activation of SARS-CoV-2 S through various c leavage sites.In this article,we review host proteases including furin,trypsin,transmembrane protease serine 2(TMPRSS2)and cathepsins in the activation of SARS-CoV-2 S.Many betacoronaviruses including SARS-CoV-2 have polybasic residues at the S1/S2 site which is subjected to the cleavage by furin.The S1/S2 cleavage facilitates more assessable RBD to the receptor ACE2,and the binding triggers further conformational changes and exposure of the S2'site to proteases such as type Il transmembrane serine proteases(TTPRs)including TMPRSS2.In the presence of TMPRSS2 on the target cells,SARS-CoV-2 can utilize a direct entry route by fusion of the viral envelope to the cellular membrane.In the absence of TMPRSS2,SARS-CoV-2 enter target cells via endosomes where multiple cathepsins cleave the S for the successful entry.Additional host proteases involved in the cleavage of the S were discussed.This article also includes roles of 3C-like protease inhibitors which have inhibitory activity against cathepsin L in the entry of SARS-CoV-2,and discussed the dual roles of such inhibitors in virus replication.展开更多
In a recent review paper,Carroll and Maharshak discussed a critical role of enteric bacterial proteases in the pathogenesis of inflammatory bowel disease(IBD).I take a great interest in this paper as I also suspected ...In a recent review paper,Carroll and Maharshak discussed a critical role of enteric bacterial proteases in the pathogenesis of inflammatory bowel disease(IBD).I take a great interest in this paper as I also suspected proteases,not from the bacteria,but those originated from the pancreas that failed to be inactivated in the lower gut due to a reduction in gut bacteria,may have played a critical role in the pathogenesis of IBD,which was first published more than a decade ago and discussed again in more detail in a recent paper published in this journal.Antibiotics may result in a big reduction in gut bacteria and bacterial proteases,but multiple studies demonstrated dramatic increased of pancreatic proteases like trypsin and chymotrypsin in the feces of animals or patients treated with antibiotics.Multiple large-scale studies also demonstrated use of antibiotics caused an increase but not decrease in the risk of developing IBD,suggesting impaired inactivation and degradation of pancreatic proteases may have played a more critical role in the pathogenesis of IBD.展开更多
107 strains producing protease were screened from 260 strains of Antarctic psychrophilic bacteria, among which proteolytic activity of five strains was more than 45 U ml^-1. The 16S rRNA gcne sequences homology and ph...107 strains producing protease were screened from 260 strains of Antarctic psychrophilic bacteria, among which proteolytic activity of five strains was more than 45 U ml^-1. The 16S rRNA gcne sequences homology and phylogcnetic analysis of five Antarctic psychrophillc bacteria showed that NJ276, NJS-9, NJ16-70,NJ345 belonged tO the described genus Pseudoalteromonas and NJ341 belonged to the genus Colwellia. The growth and the protease characteristic of four Antarctic psychrophilic bacteria had been studied, and the result showed that the 6ptimal temperature for growth and protease-produeing of four strains was about 10℃. Their growth and protease-produeing were still high during incubatlng 2-5 days. The maximum proteolytic activity occurred at pH 9 for four Antarctic psychrophilic bacteria. The optimal temperature of protease action of both strains NJ276 and NJ5-9 was about 50℃, however, the optimal temperature of protease aetlon of both strains NJ341 and NJ345 was about 40 ℃, and their proteolytic activity under 0℃ exhibited nearly 30% of the maximum activity, but their thermal stabilities were weaker. These results indicated that proteases from NJ341 and NJ345 were low-temperature proteases.展开更多
Despite the global decline in the severity of the coronavirus disease 2019 (COVID-19) cases, the disease stillrepresents a major concern to the relevant scientific and medical communities. The primary concern of drug ...Despite the global decline in the severity of the coronavirus disease 2019 (COVID-19) cases, the disease stillrepresents a major concern to the relevant scientific and medical communities. The primary concern of drug scientists,virologists, and other concerned specialists in this respect is to find ready-to-use suitable and potent anticoronaviraltherapies that are broadly effective against the different species/strains of the coronaviruses in general, not only againstthe current and previous coronaviruses (e.g., the recently-appeared severe acute respiratory syndrome coronavirus 2“SARS-CoV-2”), i.e., effective antiviral agents for treatment and/or prophylaxis of any coronaviral infections, includingthose of the coming ones from the next species and strains (if any). As an expert in this field, I tried, in this up-to-dateperspective “viewpoint” article, to evaluate the suitability and applicability of using the currently-availableanticoronaviral agents for the next coronavirus diseases (COVIDs) and coronaviral pandemics, highlighting the mostimportant general guidelines that should be considered in the next pandemics from the therapeutic points of view.展开更多
基金National Institutes of Health(NIH)(grants R01 A/130092 and Al161085).
文摘The spike protein(S)of SARS-CoV-2 is responsible for viral attachment and entry,thus a major factor for host suscep-tibility,tissue tropism,virulence and pathogenicity.The S is divided with S1 and S2 region,and the S1 contains the receptor-binding domain(RBD),while the S2 contains the hydrophobic fusion domain for the entry into the host cell.Numerous host proteases have been implicated in the activation of SARS-CoV-2 S through various c leavage sites.In this article,we review host proteases including furin,trypsin,transmembrane protease serine 2(TMPRSS2)and cathepsins in the activation of SARS-CoV-2 S.Many betacoronaviruses including SARS-CoV-2 have polybasic residues at the S1/S2 site which is subjected to the cleavage by furin.The S1/S2 cleavage facilitates more assessable RBD to the receptor ACE2,and the binding triggers further conformational changes and exposure of the S2'site to proteases such as type Il transmembrane serine proteases(TTPRs)including TMPRSS2.In the presence of TMPRSS2 on the target cells,SARS-CoV-2 can utilize a direct entry route by fusion of the viral envelope to the cellular membrane.In the absence of TMPRSS2,SARS-CoV-2 enter target cells via endosomes where multiple cathepsins cleave the S for the successful entry.Additional host proteases involved in the cleavage of the S were discussed.This article also includes roles of 3C-like protease inhibitors which have inhibitory activity against cathepsin L in the entry of SARS-CoV-2,and discussed the dual roles of such inhibitors in virus replication.
文摘In a recent review paper,Carroll and Maharshak discussed a critical role of enteric bacterial proteases in the pathogenesis of inflammatory bowel disease(IBD).I take a great interest in this paper as I also suspected proteases,not from the bacteria,but those originated from the pancreas that failed to be inactivated in the lower gut due to a reduction in gut bacteria,may have played a critical role in the pathogenesis of IBD,which was first published more than a decade ago and discussed again in more detail in a recent paper published in this journal.Antibiotics may result in a big reduction in gut bacteria and bacterial proteases,but multiple studies demonstrated dramatic increased of pancreatic proteases like trypsin and chymotrypsin in the feces of animals or patients treated with antibiotics.Multiple large-scale studies also demonstrated use of antibiotics caused an increase but not decrease in the risk of developing IBD,suggesting impaired inactivation and degradation of pancreatic proteases may have played a more critical role in the pathogenesis of IBD.
基金supported by Program of National Natural Science Foundation of China.(No.40406003)
文摘107 strains producing protease were screened from 260 strains of Antarctic psychrophilic bacteria, among which proteolytic activity of five strains was more than 45 U ml^-1. The 16S rRNA gcne sequences homology and phylogcnetic analysis of five Antarctic psychrophillc bacteria showed that NJ276, NJS-9, NJ16-70,NJ345 belonged tO the described genus Pseudoalteromonas and NJ341 belonged to the genus Colwellia. The growth and the protease characteristic of four Antarctic psychrophilic bacteria had been studied, and the result showed that the 6ptimal temperature for growth and protease-produeing of four strains was about 10℃. Their growth and protease-produeing were still high during incubatlng 2-5 days. The maximum proteolytic activity occurred at pH 9 for four Antarctic psychrophilic bacteria. The optimal temperature of protease action of both strains NJ276 and NJ5-9 was about 50℃, however, the optimal temperature of protease aetlon of both strains NJ341 and NJ345 was about 40 ℃, and their proteolytic activity under 0℃ exhibited nearly 30% of the maximum activity, but their thermal stabilities were weaker. These results indicated that proteases from NJ341 and NJ345 were low-temperature proteases.
文摘Despite the global decline in the severity of the coronavirus disease 2019 (COVID-19) cases, the disease stillrepresents a major concern to the relevant scientific and medical communities. The primary concern of drug scientists,virologists, and other concerned specialists in this respect is to find ready-to-use suitable and potent anticoronaviraltherapies that are broadly effective against the different species/strains of the coronaviruses in general, not only againstthe current and previous coronaviruses (e.g., the recently-appeared severe acute respiratory syndrome coronavirus 2“SARS-CoV-2”), i.e., effective antiviral agents for treatment and/or prophylaxis of any coronaviral infections, includingthose of the coming ones from the next species and strains (if any). As an expert in this field, I tried, in this up-to-dateperspective “viewpoint” article, to evaluate the suitability and applicability of using the currently-availableanticoronaviral agents for the next coronavirus diseases (COVIDs) and coronaviral pandemics, highlighting the mostimportant general guidelines that should be considered in the next pandemics from the therapeutic points of view.
