Substrate specificity and screening of the integral membrane protease Pla.
Ontology highlight
ABSTRACT:
SUBMITTER: Agarkov A
PROVIDER: S-EPMC2263006 | biostudies-literature | 2008 Jan
REPOSITORIES: biostudies-literature
Publications
Substrate specificity and screening of the integral membrane protease Pla.
Agarkov Anton A Chauhan Sadhana S Lory Pedro J PJ Gilbertson Scott R SR Motin Vladimir L VL
Bioorganic & medicinal chemistry letters 20071012 1
This paper reports a study to find small peptide substrates for the important virulence factor of Yersinia pestis, plasminogen activator, Pla. The method used to find small substrates for this protease is reported along with studies examining the ability of these peptides to inhibit activity of the enzyme. Through the use of parallel synthesis and positional scanning, small tripeptides were identified that are viable substrates for the protease. ...[more]
Similar Datasets
Project description:Escherichia coli OmpP is an F episome-encoded outer membrane protease that exhibits 71% amino acid sequence identity with OmpT. These two enzymes cleave substrate polypeptides primarily between pairs of basic amino acids. We found that, like OmpT, purified OmpP is active only in the presence of lipopolysaccharide. With optimal peptide substrates, OmpP exhibits high catalytic efficiency (k(cat)/K(m) = 3.0 x 10(6) M(-1)s(-1)). Analysis of the extended amino acid specificity of OmpP by substrate phage revealed that both Arg and Lys are strongly preferred at the P1 and P1' sites of the enzyme. In addition, Thr, Arg, or Ala is preferred at P2; Leu, Ala, or Glu is preferred at P4; and Arg is preferred at P3'. Notable differences in OmpP and OmpT specificities include the greater ability of OmpP to accept Lys at the P1 or P1', site as well as the prominence of Ser at P3 in OmpP substrates. Likewise, the OmpP P1 site could better accommodate Ser; as a result, OmpP was able to cleave a peptide substrate between Ser-Arg about 120 times more efficiently than was OmpT. Interestingly, OmpP and OmpT cleave peptides with three consecutive Arg residues at different sites, a difference in specificity that might be important in the inactivation of cationic antimicrobial peptides. Accordingly, we show that the presence of an F' episome results in increased resistance to the antimicrobial peptide protamine both in ompT mutants and in wild-type E. coli cells.
| S-EPMC1797397 | biostudies-literature
Project description:OMA1 is a mitochondrial protease. Among its substrates are DELE1, a signaling peptide, which can elicit the integrated stress response, as well as the membrane-shaping dynamin-related GTPase OPA1, which can drive mitochondrial outer membrane permeabilization. OMA1 is dormant under physiological conditions but rapidly activated upon mitochondrial stress, such as loss of membrane potential or excessive reactive oxygen species. Accordingly, OMA1 was found to be activated in a number of disease conditions, including cancer and neurodegeneration. OMA1 has a predicted transmembrane domain and is believed to be tethered to the mitochondrial inner membrane. Yet, its structure has not been resolved and its context-dependent regulation remains obscure. Here, I review the literature with focus on OMA1's biochemistry. I provide a good homology model of OMA1's active site with a root-mean-square deviation of 0.9 Å and a DALI Z-score of 19.8. And I build a case for OMA1 actually being an integral membrane protease based on OMA1's role in the generation of small signaling peptides, its functional overlap with PARL, and OMA1's homology with ZMPSTE24. The refined understanding of this important enzyme can help with the design of tool compounds and development of chemical probes in the future.
| S-EPMC7770061 | biostudies-literature
Project description:Tulane virus (TV) is a cultivable calicivirus isolated from rhesus monkeys. In this study, we characterized the substrate specificity of TV protease in trans using recombinant proteases and TV polyprotein fragments containing the predicted proteolytic cleavage sites. Cleavage products have been obtained from 4 of the 5 fragments containing (573)Q-S(574) between the helicase and 3A-like protein, (712)E-A(713) between the 3A-like protein and Vpg, (802)E-G(803) between Vpg and the protease, and (976)E-G(977) between the protease and RdRp. We also characterized the enzymatic activities of the recombinant proteases of TV and Norwalk virus using synthetic fluorogenic peptide substrates. Under optimal conditions for enzymatic assays, partial cross-reactivities on reciprocal substrates were observed between TV and Norwalk virus proteases. The apparently shared substrate specificities between TV and Norwalk virus proteases suggested that the cultivable TV could be used as a model for in vivo evaluation of lead candidates of protease inhibitors for human norovirus.
| S-EPMC3545077 | biostudies-literature
Project description:Posttranslational lipidation provides critical modulation of the functions of some proteins. Isoprenoids (i.e., farnesyl or geranylgeranyl groups) are attached to cysteine residues in proteins containing C-terminal CAAX sequence motifs (where A is an aliphatic residue and X is any residue). Isoprenylation is followed by cleavage of the AAX amino acid residues and, in some cases, by additional proteolytic cuts. We determined the crystal structure of the CAAX protease Ste24p, a zinc metalloprotease catalyzing two proteolytic steps in the maturation of yeast mating pheromone a-factor. The Ste24p core structure is a ring of seven transmembrane helices enclosing a voluminous cavity containing the active site and substrate-binding groove. The cavity is accessible to the external milieu by means of gaps between splayed transmembrane helices. We hypothesize that cleavage proceeds by means of a processive mechanism of substrate insertion, translocation, and ejection.
| S-EPMC4136949 | biostudies-literature
Project description:Omptins constitute a unique family of outer membrane proteases that are widespread in Enterobacteriaceae. The plasminogen activator (Pla) of Yersinia pestis is an omptin family member that is very important for development of both bubonic and pneumonic plague. The physiological function of Pla is to cleave (activate) human plasminogen to form the plasma protease plasmin. Uniquely, lipopolysaccharide (LPS) is essential for the catalytic activity of all omptins, including Pla. Why omptins require LPS for enzymatic activity is unknown. Here, we report the co-crystal structure of LPS-free Pla in complex with the activation loop peptide of human plasminogen, its natural substrate. The structure shows that in the absence of LPS, the peptide substrate binds deep within the active site groove and displaces the nucleophilic water molecule, providing an explanation for the dependence of omptins on LPS for enzymatic activity.
| S-EPMC3390672 | biostudies-literature
Project description:A series of putative dipeptide substrates of prostate-specific membrane antigen (PSMA) was prepared that explored alpha- and beta/gamma-linked acidic residues at the P1 position and various chromophores at the P2 position, while keeping the P1' residue constant as L-Glu. Four chromophores were examined, including 4-phenylazobenzoyl, 1-pyrenebutyryl, 9-anthracenylcarboxyl-gamma-aminobutyryl, and 4-nitrophenylbutyryl. When evaluating these chromophores, it was found that a substrate containing 4-phenylazobenzoyl at the P2 position was consumed most efficiently. Substitution at the P1 position with acidic residues showed that only gamma-linked L-Glu and D-Glu were recognized by the enzyme, with the former being more readily proteolyzed. Lastly, binding modes of endogenous substrates and our best synthetic substrate (4-phenylazobenzoyl-Glu-gamma-Glu) were proposed by computational docking studies into an X-ray crystal structure of the PSMA extracellular domain.
| S-EPMC2014784 | biostudies-literature
Project description:Many pathogens usurp the host hemostatic system during infection to promote pathogenesis. Yersinia pestis, the causative agent of plague, expresses the plasminogen activator protease Pla, which has been shown in vitro to target and cleave multiple proteins within the fibrinolytic pathway, including the plasmin inhibitor ?2-antiplasmin (A2AP). It is not known, however, if Pla inactivates A2AP in vivo; the role of A2AP during respiratory Y. pestis infection is not known either. Here, we show that Y. pestis does not appreciably cleave A2AP in a Pla-dependent manner in the lungs during experimental pneumonic plague. Furthermore, following intranasal infection with Y. pestis, A2AP-deficient mice exhibit no difference in survival time, bacterial burden in the lungs, or dissemination from wild-type mice. Instead, we found that in the absence of Pla, A2AP contributes to the control of the pulmonary inflammatory response during infection by reducing neutrophil recruitment and cytokine production, resulting in altered immunopathology of the lungs compared to A2AP-deficient mice. Thus, our data demonstrate that A2AP is not significantly affected by the Pla protease during pneumonic plague, and although A2AP participates in immune modulation in the lungs, it has limited impact on the course or ultimate outcome of the infection.
| S-EPMC4645379 | biostudies-literature
Project description:Lacticin 481 is a lanthionine-containing bacteriocin (lantibiotic) produced by Lactococcus lactis subsp. lactis. The final steps of lacticin 481 biosynthesis are proteolytic removal of an N-terminal leader sequence from the prepeptide LctA and export of the mature lantibiotic. Both proteolysis and secretion are performed by the dedicated ATP-binding cassette (ABC) transporter LctT. LctT belongs to the family of AMS (ABC transporter maturation and secretion) proteins whose prepeptide substrates share a conserved double-glycine type cleavage site. The in vitro activity of a lantibiotic protease has not yet been characterized. This study reports the purification and in vitro activity of the N-terminal protease domain of LctT (LctT150), and its use for the in vitro production of lacticin 481. The G(-2)A(-1) cleavage site and several other conserved amino acid residues in the leader peptide were targeted by site-directed mutagenesis to probe the substrate specificity of LctT as well as shed light upon the role of these conserved residues in lantibiotic biosynthesis. His 10-LctT150 did not process most variants of the double glycine motif and processed mutants of Glu-8 only very slowly. Furthermore, incorporation of helix-breaking residues in the leader peptide resulted in greatly decreased proteolytic activity by His 10-LctT150. On the other hand, His 10-LctT150 accepted all peptides containing mutations in the propeptide or at nonconserved positions of LctA. In addition, the protease domain of LctT was investigated by site-directed mutagenesis of the conserved residues Cys12, His90, and Asp106. The proteolytic activities of the resulting mutant proteins are consistent with a cysteine protease.
| S-EPMC2574596 | biostudies-literature
Project description:Tobacco vein mottling virus (TVMV) is a member of the Potyviridae, one of the largest families of plant viruses. The TVMV genome is translated into a single large polyprotein that is subsequently processed by three virally encoded proteases. Seven of the nine cleavage events are carried out by the NIa protease. Its homolog from the tobacco etch virus (TEV) is a widely used reagent for the removal of affinity tags from recombinant proteins. Although TVMV protease is a close relative of TEV protease, they exhibit distinct sequence specificities. We report here the crystal structure of a catalytically inactive mutant TVMV protease (K65A/K67A/C151A) in complex with a canonical peptide substrate (Ac-RETVRFQSD) at 1.7-Å resolution. As observed in several crystal structures of TEV protease, the C-terminus (?20 residues) of TVMV protease is disordered. Unexpectedly, although deleting the disordered residues from TEV protease reduces its catalytic activity by ?10-fold, an analogous truncation mutant of TVMV protease is significantly more active. Comparison of the structures of TEV and TVMV protease in complex with their respective canonical substrate peptides reveals that the S3 and S4 pockets are mainly responsible for the differing substrate specificities. The structure of TVMV protease suggests that it is less tolerant of variation at the P1' position than TEV protease. This conjecture was confirmed experimentally by determining kinetic parameters k(cat) and K(m) for a series of oligopeptide substrates. Also, as predicted by the cocrystal structure, we confirm that substitutions in the P6 position are more readily tolerated by TVMV than TEV protease.
| S-EPMC3005794 | biostudies-literature
Project description:BACKGROUND: Omptins are a family of outer membrane proteases that have spread by horizontal gene transfer in Gram-negative bacteria that infect vertebrates or plants. Despite structural similarity, the molecular functions of omptins differ in a manner that reflects the life style of their host bacteria. To simulate the molecular adaptation of omptins, we applied site-specific mutagenesis to make Epo of the plant pathogenic Erwinia pyrifoliae exhibit virulence-associated functions of its close homolog, the plasminogen activator Pla of Yersinia pestis. We addressed three virulence-associated functions exhibited by Pla, i.e., proteolytic activation of plasminogen, proteolytic degradation of serine protease inhibitors, and invasion into human cells. RESULTS: Pla and Epo expressed in Escherichia coli are both functional endopeptidases and cleave human serine protease inhibitors, but Epo failed to activate plasminogen and to mediate invasion into a human endothelial-like cell line. Swapping of ten amino acid residues at two surface loops of Pla and Epo introduced plasminogen activation capacity in Epo and inactivated the function in Pla. We also compared the structure of Pla and the modeled structure of Epo to analyze the structural variations that could rationalize the different proteolytic activities. Epo-expressing bacteria managed to invade human cells only after all extramembranous residues that differ between Pla and Epo and the first transmembrane ?-strand had been changed. CONCLUSIONS: We describe molecular adaptation of a protease from an environmental setting towards a virulence factor detrimental for humans. Our results stress the evolvability of bacterial ?-barrel surface structures and the environment as a source of progenitor virulence molecules of human pathogens.
| S-EPMC3048539 | biostudies-literature