scholarly journals Specificity of S'1 and S'2 subsites of human tissue kallikrein using the reactive-centre loop of kallistatin: the importance of P'1 and P'2 positions in design of inhibitors

2003 ◽  
Vol 371 (3) ◽  
pp. 1021-1025 ◽  
Author(s):  
Daniel C. PIMENTA ◽  
Sandro E. FOGAÇA ◽  
Robson L. MELO ◽  
Luiz JULIANO ◽  
Maria A. JULIANO

We have demonstrated that the S´1 and S´2 subsites of human tissue kallikrein (hK1) play determinant roles in the recognition and hydrolysis of substrates. The presence of serine at position P´1 and arginine at P´2 resulted in the best substrate, Abz-Ala-Ile-Lys-Phe-Phe-Ser-Arg-Gln-EDDnp, which was derived from the kallistatin reactive-centre loop sequence and quencher groups o-aminobenzoic acid (Abz) and N-(2,4-dinitrophenyl)ethylenediamine (EDDnp). Serine and arginine are also the residues at positions P´1 and P´2 in human kininogen, from which hK1 releases Lys-bradykinin. Several peptide analogues of Abz-Ala-Ile-Lys-Phe-Phe-Ser-Arg-Gln-EDDnp, in which the Ser and Arg residues were substituted with various other amino acids, were synthesized and tested as substrates. Most of them were hydrolysed slowly, although they showed significant binding to hK1, as demonstrated by their competitive inhibition constants (Ki). Using this information, six peptides were designed, synthesized and assayed as inhibitors of hK1. Abz-Lys-Phe-Phe-Pro-Arg-Gln-EDDnp, Abz-Lys-Phe-Arg-Pro-Arg-Gln-EDDnp and acetyl-Lys-Phe-Phe-Pro-Leu-Glu-NH2 inhibited hK1 in the range 20–30 nM (letters in italics denote the d-form of the amino acid). The peptide acetyl-Lys-Phe-Phe-Pro-Leu-Glu-NH2 was a weak inhibitor for other serine proteases, as indicated by the higher Ki values compared with hK1, but this peptide was a potent inhibitor of human plasma kallikrein, which has a Ki value of 8 nM. This result was surprising, since this enzyme is known to be a restricted arginyl-hydrolase. In conclusion, acetyl-Lys-Phe-Phe-Pro-Leu-Glu-NH2 can be used as a leader compound to design specific inhibitors for hK1, plasma kallikrein, or for both at same time, if the inhibition of kinin release is the main goal.

1999 ◽  
Vol 339 (2) ◽  
pp. 473-479 ◽  
Author(s):  
Daniel C. PIMENTA ◽  
Julie CHAO ◽  
Lee CHAO ◽  
Maria A. JULIANO ◽  
Luiz JULIANO

We have explored in detail the determinants of specificity for the hydrolysis by human tissue kallikrein (hK1) of substrates containing the Phe–Phe amino acid pair, after which hK1 cleaves kallistatin (human kallikrein-binding protein), a specific serpin for this protease, as well as somatostatin 1–14. Internally quenched fluorogenic peptides were synthesized with the general structure Abz-peptidyl-EDDnp [Abz, o-aminobenzoic acid; EDDnp, N-(2,4-dinitrophenyl)ethylenediamine], based on the natural reactive-centre loop sequence of kallistatin from P9 to P´13, and the kinetic parameters of their hydrolysis by hK1 were determined. All these peptides were cleaved after the Phe–Phe pair. For comparison, we have also examined peptides containing the reactive-centre loop sequences of human protein-C inhibitor (PCI) and rat kallikrein-binding protein, which were hydrolysed after Phe–Arg and Leu–Lys bonds, respectively. Hybrid peptides containing kallistatin–PCI sequences showed that the efficiency of hK1 activity on the peptides containing kallistatin and PCI sequences depended on both the nature of the P1 amino acid as well as on residues at the P- and P´-sides. Moreover, we have made systematic modifications on the hydrophobic pair Phe–Phe, and on Lys and Ile at the P3 and P4 positions according to the peptide substrate, Abz-AIKFFSRQ-EDDnp. All together, we concluded that tissue kallikrein was very effective on short substrates that are cleaved after the Phe–Arg pair; however, hydrolysis after Phe–Phe or other hydrophobic pairs of amino acids was more restrictive, requiring additional enzyme–substrate interaction and/or particular substrate conformations.


2019 ◽  
Vol 75 (1) ◽  
pp. 56-69
Author(s):  
Mi Li ◽  
Jaroslav Srp ◽  
Alla Gustchina ◽  
Zbigniew Dauter ◽  
Michael Mares ◽  
...  

Structures of a recombinant Kunitz-type serine protease inhibitor from Bauhinia bauhinioides (BbKI) complexed with bovine trypsin were determined in two crystal forms. The crystal structure with the L55R mutant of BbKI was determined in space group P64 at 1.94 Å resolution and that with native BbKI in the monoclinic space group P21 at 3.95 Å resolution. The asymmetric unit of the latter crystals contained 44 independent complexes, thus representing one of the largest numbers of independent objects deposited in the Protein Data Bank. Additionally, the structure of the complex with native BbKI was determined at 2.0 Å resolution from P64 crystals isomorphous to those of the mutant. Since BbKI has previously been found to be a potent inhibitor of the trypsin-like plasma kallikrein, it was also tested against several tissue kallikreins. It was found that BbKI is a potent inhibitor of human tissue kallikrein 4 (KLK4) and the chymotrypsin-like human tissue kallikrein 7 (KLK7). Structures of BbKI complexed with the catalytic domain of human plasma kallikrein were modeled, as well as those with KLK4 and KLK7, and the structures were analyzed in order to identify the interactions that are responsible for inhibitory potency.


1997 ◽  
Vol 327 (1) ◽  
pp. 27-30 ◽  
Author(s):  
Daniel C. PIMENTA ◽  
Maria A. JULIANO ◽  
Luiz JULIANO

Somatostatin-(1–14) was hydrolysed by human tissue kallikrein at the Phe7-Trp8 bond, after a Phe-Phe pair of amino acids, with similar kinetic parameters to those described for human high- and low-molecular-mass kininogens. Substance P and human insulin, which also contain a Phe-Phe pair in their sequences, were both resistant. More details of this hydrolytic specificity of human tissue kallikrein were obtained by synthesizing and assaying internally quenched fluorescent peptides containing the sequence of somatostatin-(1–14), as well as the reactive-centre loop of human kallikrein-binding protein (kallistatin). We also observed that human tissue kallikrein hydrolysed growth hormone-releasing hormone at the Arg11-Lys12 bond, although this peptide contains in its structure a pair of leucines (Leu22-Leu23), in contrast with the Phe-Phe pair in somatostatin. We have also demonstrated the susceptibility to human tissue kallikrein of some chromogenic peptides with the general structure X-Phe-Phe-p-nitroanilide and of d-Pro-Phe-Phe-4-methylcoumaryl-7-amide.


2009 ◽  
Vol 101 (04) ◽  
pp. 741-747 ◽  
Author(s):  
Konstantina Mathioudaki ◽  
Panagiotis Prezas ◽  
Dimitra Alexopoulou ◽  
Eleftherios Diamandis ◽  
Dimitris Xynopoulos ◽  
...  

SummaryHuman tissue kallikrein-related peptidases are a family of 15 secreted serine proteases, located at chromosome 19q13.4. Most of them have been reported to be potential biomarkers for several carcinomas and other diseases. Human tissue kallikrein-related peptidase 7 (KLK7) has been purified from human stratum corneum and resembles a chymotryptic endopeptidase originally called stratum corneum chymotryptic enzyme (SCCE). In this study, we examined for the first time, the prognostic value of KLK7 mRNA expression, using a semi-quantitative RT-PCR method, in 105 colorectal cancer tissues for 54 of which, paired normal colonic mucosa were available. Furthermore, we analysed the expression of KLK7 in 10 adenomas, in 18 biopsies of inflamed colon mucosa, as well as in 22 human cancer cell lines of various origin, four of them being of colon. A defined number of colon cancer samples were also examined by immunohisto-chemistry. KLK7 expression was higher in cancerous than in normal tissues. Less differentiated tumors of more advanced stage showed higher KLK7 expression. Follow-up analysis revealed that KLK7 was significantly associated with shorter overall survival (OS) and disease-free survival (DFS). In addition, selected colon cancer samples highly expressing KLK7 gene, showed intense immunohistochemical staining for KLK7, enhancing RTPCR results. Present data suggest that KLK7 gene is up-regulated in colon cancer and its expression predicts poor prognosis for colon cancer patients.


2015 ◽  
Vol 71 (8) ◽  
pp. 1055-1062 ◽  
Author(s):  
Dongwen Zhou ◽  
Daiane Hansen ◽  
Ivan G. Shabalin ◽  
Alla Gustchina ◽  
Debora F. Vieira ◽  
...  

A serine protease inhibitor fromBauhinia bauhinioides(BbKI) belongs to the Kunitz family of plant inhibitors, which are common in plant seeds. BbKI does not contain any disulfides, unlike most other members of this family. It is a potent inhibitor of plasma kallikrein, in addition to other serine proteases, and thus exhibits antithrombotic activity. A high-resolution crystal structure of recombinantly expressed BbKI was determined (at 1.4 Å resolution) and was compared with the structures of other members of the family. Modeling of a complex of BbKI with plasma kallikrein indicates that changes in the local structure of the reactive loop that includes the specificity-determining Arg64 are necessary in order to explain the tight binding. An R64A mutant of BbKI was found to be a weaker inhibitor of plasma kallikrein, but was much more potent against plasmin, suggesting that this mutant may be useful for preventing the breakup of fibrin and maintaining clot stability, thus preventing excessive bleeding.


1995 ◽  
Vol 312 (1) ◽  
pp. 233-238 ◽  
Author(s):  
E Del Nery ◽  
J R Chagas ◽  
M A Juliano ◽  
E S Prado ◽  
L Juliano

We have synthesized internally quenched peptides spanning the Met379-Lys380 or Arg389-Ser390 bonds of human kininogen (hkng) that flank lysyl-bradykinin and have studied the kinetics of their hydrolysis by human tissue kallikrein. The kinetic data for the hydrolysis of the Met-Lys bond in substrates with an N-terminal extension showed that interactions up to position residue P10 contribute to the efficiency of cleavage. In contrast, there were no significant variations in the kinetic data for the hydrolysis of substrates with C-terminal extensions at sites P′4 to P′11. A similar pattern was observed for the cleavage of substrates containing an Arg-Ser bond because substrates extended up to residue P6 were hydrolysed with the highest kcat/Km values in the series, whereas those extended to P′11 on the C-terminal side had a lower susceptibility to hydrolysis. Time-course studies of hydrolysis by human and porcine tissue kallikreins of a Leu373 to Ile393 human kininogen fragment containing omicron-aminobenzoic acid (Abz) at the N-terminus and an amidated C-terminal carboxyl group Abz-Leu-Gly-Met-Ile-Ser-Leu-Met-Lys-Arg- Pro-Pro-Gly-Phe-Ser-Pro-Phe-Arg-Ser-Ser-Arg-Ile-NH2 (Abz-[Leu373-Ile393]-hkng-NH2) indicated that the cleavage of Met-Lys and Arg-Ser bonds in the same molecule occurs via the formation of independent enzyme-substrate complexes. The hydrolysis of Abz-F-R-S-S-R-Q-EDDnp [where EDDnp is N-(2,4-dinitrophenyl)ethylenediamine] and Abz-M-I-S-L-M-K-R-P-Q-EDDnp by human tissue kallikrein had maximal kcat/Km values at pH 9-9.5 for both substrates. The pH-dependent variations in this kinetic parameter were almost exclusively due to variations in kcat. A significant decrease in kcat/Km values was observed for the hydrolysis of Arg-Ser and Met-Lys bonds in the presence of 0.1 M NaCl. Because this effect was closely related to an increase in Km, it is likely that sodium competes with the positive charges of the substrate side chains for the same enzyme subsites.


2008 ◽  
Vol 389 (12) ◽  
Author(s):  
Aurelio Resende Lima ◽  
Fabiana M. Alves ◽  
Pedro Francisco Ângelo ◽  
Douglas Andrade ◽  
Sachiko I. Blaber ◽  
...  

AbstractThe S1′ and S2′ subsite specificities of human tissue kallikrein 1 (KLK1) and human plasma kallikrein (HPK) were examined with the peptide series Abz-GFSPFRXSRIQ-EDDnp and Abz-GFSPFRSXRIQ-EDDnp [X=natural amino acids or S(PO3H2)]. KLK1 efficiently hydrolyzed most of the peptides except those containing negatively charged amino acids at P1′ and P2′ positions. Abz-GFSPFRSSRIQ-EDDnp, as in human kininogen, is the best substrate for KLK1 and exclusively cleaved the R-S bond. All other peptides were cleaved also at the F-R bond. The synthetic human kininogen segment Abz-MISLMKRPPGFSPFRS390S391RI-NH2was hydrolyzed by KLK1 first at R-S and then at M-K bonds, releasing Lys-bradykinin. In the S390and S391phosphorylated analogs, this order of hydrolysis was inverted due to the higher resistance of the R-S bond. Abz-MISLMKRPPG-FSPFRSS(PO3H2)391RI-NH2was hydrolyzed by KLK1 at M-K and mainly at the F-R bond, releasing des-(Arg9)-Lys-Bk which is a B1 receptor agonist. HPK cleaved all the peptides at R and showed restricted specificity for S in the S1′ subsite, with lower specificity for the S2′ subsite. Abz-MISLMKRPPGFSPFRSSRI-NH2was efficiently hydrolyzed by HPK under bradykinin release, while the analogs containing S(PO3H2) were poorly hydrolyzed. In conclusion, S1′ and S2′ subsite specificities of KLK1 and HPK showed peculiarities that were observed with substrates containing the amino acid sequence of human kininogen.


2008 ◽  
Vol 389 (11) ◽  
Author(s):  
Julie L.V. Shaw ◽  
Eleftherios P. Diamandis

AbstractHuman tissue kallikrein-related peptidases (KLK), which are secreted serine proteases, are encoded by 15 genes located on chromosome 19q13.4. Previous studies have shown thatKLKexpression is regulated by steroid hormones and many KLKs are dysregulated in hormone-dependent malignancies. Some KLKs are proposed biomarkers for these cancers. We have characterized KLK hormonal regulation patterns using a large number of human cell lines. KLK levels were quantified in supernatants from 32 cell lines, each subjected to four hormonal stimulations (dexamethasone, norgestrel, dihydrotestosterone or estradiol), using ELISAs. Cell lines included breast, prostate, ovarian, lung, pancreatic, colon, and cervical cancer cells, T-lymphocytes, keratinocytes and a non-cancerous epithelial breast cell line. KLKs were regulated in several cell lines not previously studied, such as keratinocytes (KLK5, 6, and 7), ovarian cancer (KLK5 and 9) and cervical cancer (KLK3, 5, 6, 7, 8, 10, 11, and 13) cells. Many KLKs were regulated by the synthetic glucocorticoid dexamethasone; specifically, KLK5, 6, 8, 10 and 11 were upregulated in several breast cancer cell lines and downregulated in several cervical cancer cell lines. Knowledge of KLK hormonal regulation patterns will help to shed further light on their potential use as biomarkers and therapeutic targets for hormone-related malignancies.


Blood ◽  
1987 ◽  
Vol 69 (5) ◽  
pp. 1431-1436
Author(s):  
CF Scott ◽  
HR Wenzel ◽  
HR Tschesche ◽  
RW Colman

Human plasma kallikrein, a product of contact-activated plasma proteolysis, is moderately inhibited by aprotinin, a small polypeptide from bovine lung that has been used as an experimental drug in human disease states. Aprotinin has a Lys residue in the P1 (reactive center) position occupying residue 15. Since kallikrein is an arginine-directed serine protease, we hypothesized that an altered form of aprotinin, Arg15-aprotinin, might be a better inhibitor. Kinetic evaluations were performed in 96-well microplates. We found that the KL (loose or Michaelis-Menten complex) was unchanged by the modification. However, the association rate constant was increased from 1.14 X 10(4) (mol/L)- 1s-1 to 1.5 X 10(5) (mol/L)-1s1, thus indicating that the inhibition rate was increased 14-fold for the modified protein. The Ki (at equilibrium) was decreased from 3.2 X 10(-7) mol/L to 1.5 X 10(-8) mol/L after substituting Arg for Lys in the P1 position. Therefore, the modified inhibitor binds to plasma kallikrein more tightly than the natural protein. We also investigated the effect of Arg15-aprotinin on tissue kallikrein, plasmin, factor XIIa, factor XIa, and thrombin and found that the Ki slightly decreased from 5.1 X 10(-7) mol/L to 1.2 X 10(-7) mol/L for tissue kallikrein and slightly decreased from 2 X 10(- 8) mol/L to 1 X 10(-8) mol/L for plasmin. Arg15-aprotinin did not inhibit thrombin or factor XIIa, even though both enzymes are arginine- directed serine proteases. However, factor XIa, although it was not inhibited by aprotinin, had a Ki of 3.4 X 10(-8) mol/L for Arg15- aprotinin. Therefore, Arg15-aprotinin is a more effective inhibitor of plasma kallikrein as well as factor XIa but shows minimal preference for plasmin and tissue kallikrein. This study also indicates that it is possible and practical to perform kinetic analyses directly in microplates.


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