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Szabó A, Pilsak C, Bence M, Witt H, Sahin-Tóth M. Complex Formation of Human Proelastases with Procarboxypeptidases A1 and A2. J Biol Chem 2016; 291:17706-16. [PMID: 27358403 DOI: 10.1074/jbc.m116.743237] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2016] [Indexed: 01/16/2023] Open
Abstract
The pancreas secretes digestive proenzymes typically in their monomeric form. A notable exception is the ternary complex formed by proproteinase E, chymotrypsinogen C, and procarboxypeptidase A (proCPA) in cattle and other ruminants. In the human and pig pancreas binary complexes of proCPA with proelastases were found. To characterize complex formation among human pancreatic protease zymogens in a systematic manner, we performed binding experiments using recombinant proelastases CELA2A, CELA3A, and CELA3B; chymotrypsinogens CTRB1, CTRB2, CTRC, and CTRL1; and procarboxypeptidases CPA1, CPA2, and CPB1. We found that proCELA3B bound not only to proCPA1 (KD 43 nm) but even more tightly to proCPA2 (KD 18 nm), whereas proCELA2A bound weakly to proCPA1 only (KD 152 nm). Surprisingly, proCELA3A, which shares 92% identity with proCELA3B, did not form stable complexes due to the evolutionary replacement of Ala(241) with Gly. The polymorphic nature of position 241 in both CELA3A (∼4% Ala(241) alleles) and CELA3B (∼2% Gly(241) alleles) points to individual variations in complex formation. The functional effect of complex formation was delayed procarboxypeptidase activation due to increased affinity of the inhibitory activation peptide, whereas proelastase activation was unchanged. We conclude that complex formation among human pancreatic protease zymogens is limited to a subset of proelastases and procarboxypeptidases. Complex formation stabilizes the inhibitory activation peptide of procarboxypeptidases and thereby increases zymogen stability and controls activation.
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Affiliation(s)
- András Szabó
- From the Department of Molecular and Cell Biology and
| | - Claudia Pilsak
- From the Department of Molecular and Cell Biology and the Paediatric Nutritional Medicine, Klinikum rechts der Isar (MRI), Else Kröner-Fresenius-Zentrum für Ernährungsmedizin (EKFZ), Technische Universität München (TUM), 85354 Freising, Germany, and
| | - Melinda Bence
- From the Department of Molecular and Cell Biology and
| | - Heiko Witt
- the Paediatric Nutritional Medicine, Klinikum rechts der Isar (MRI), Else Kröner-Fresenius-Zentrum für Ernährungsmedizin (EKFZ), Technische Universität München (TUM), 85354 Freising, Germany, and the ZIEL-Institute for Food and Health, 85354 Freising, Germany
| | - Miklós Sahin-Tóth
- From the Department of Molecular and Cell Biology and Center for Exocrine Disorders, Boston University Henry M. Goldman School of Dental Medicine, Boston, Massachusetts 02118,
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Seddi R, Chaix JC, Puigserver A, Guo XJ. Expression of a soluble and activatable form of bovine procarboxypeptidase A in Escherichia coli. Protein Expr Purif 2003; 27:220-8. [PMID: 12597880 DOI: 10.1016/s1046-5928(02)00573-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Bovine pancreatic procarboxypeptidase A has been overexpressed in a soluble and activatable form in Escherichia coli. When the protein was expressed under the control of bacteriophage T7 promoter in E. coli ADA494 (a thioredoxin reductase deficient bacteria), a thioredoxin fusion protein was produced at relatively high level in the cytoplasm (4 mg/L culture medium). Although the recombinant protein essentially accumulated as inclusion bodies, as much as 30% of the fusion protein was recovered in a soluble form at low growth temperature and could therefore be purified to homogeneity in a single-step procedure by metal-affinity chromatography. The recombinant precursor form of bovine carboxypeptidase A was recognized by a monoclonal antibody directed against purified bovine pancreatic carboxypeptidase A. Moreover, upon tryptic activation it gave rise to an enzyme, the N-terminal sequence, molecular size,and specific activity of which were comparable to those of the enzyme derived from the native precursor purified from bovine pancreas.
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Affiliation(s)
- Rachid Seddi
- Institut Méditerranéen de Recherche en Nutrition, Service 342, UMR Université Aix-Marseille III-INRA 1111, Faculté des Sciences et Techniques de Saint-Jérôme, Avenue Escadrille Normandie Niemen, 13397 Marseille Cedex 20, France
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Vendrell J, Querol E, Avilés FX. Metallocarboxypeptidases and their protein inhibitors. Structure, function and biomedical properties. BIOCHIMICA ET BIOPHYSICA ACTA 2000; 1477:284-98. [PMID: 10708864 DOI: 10.1016/s0167-4838(99)00280-0] [Citation(s) in RCA: 119] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Among the different aspects of recent progress in the field of metallocarboxypeptidases has been the elucidation of the three dimensional structures of the pro-segments (in monomeric or oligomeric species) and their role in the expression, folding and inhibition/activation of the pancreatic and pancreatic-like forms. Also of great significance has been the cloning and characterization of several new regulatory carboxypeptidases, enzymes that are related with important functions in protein and peptide processing and that show significant structural differences among them and also with the digestive ones. Many regulatory carboxypeptidases lack a pro-region, unlike the digestive forms or others in between from the evolutionary point of view. Finally, important advances have been made on the finding and characterization of new protein inhibitors of metallocarboxypeptidases, some of them with interesting potential applications in the biotechnological/biomedical fields. These advances are analyzed here and compared with the earlier observations in this field, which was first explored by Hans Neurath and collaborators.
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Affiliation(s)
- J Vendrell
- Departament de Bioquímica i Biologia Molecular, Facultat de Ciències, and Institut de Biologia Fonamental. Universitat Autònoma de Barcelona, E-08193, Bellaterra, Spain
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Kleene R, Kastner B, Rösser R, Kern H. Complex formation among rat pancreatic secretory proteins under mild alkaline pH conditions. Digestion 1999; 60:305-13. [PMID: 10394024 DOI: 10.1159/000007676] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Previous in vitro studies have demonstrated that enzyme proteins liberated from isolated zymogen granules of the rat pancreas aggregate already at neutral or slightly basic pH and form small particles which in the acidic pH range progressively condense into dense cores of about the size of zymogen granules. To characterize the protein composition of the original particles in more detail non-denaturing agarose gel electrophoresis was employed. Five major protein complexes were identified which upon separation of individual complexes in 1-D or 2-D gel electrophoresis were shown to be composed of a distinct set of known enzymes and several unknown proteins. Complexes 1-4 quickly dissociated when enzyme activation was induced by enterokinase, but complex 5 was resistant even to this treatment. All 5 complexes revealed a distinct fine structure when eluted from the gels and studied in negative staining electron microscopy. These findings suggest that pancreatic zymogens form complexes already in the lumen of the rough endoplasmic reticulum and are transported as such to the Golgi complex where they aggregate into granule cores due to the internal acidic pH. Complex formation may thus facilitate zymogen sorting within the rough endoplasmic reticulum and may prevent premature enzyme activation within cellular compartments.
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Affiliation(s)
- R Kleene
- Department of Cell Biology and Cell Pathology, Philipps University, Marburg, Germany.
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Khan AR, James MN. Molecular mechanisms for the conversion of zymogens to active proteolytic enzymes. Protein Sci 1998; 7:815-36. [PMID: 9568890 PMCID: PMC2143990 DOI: 10.1002/pro.5560070401] [Citation(s) in RCA: 342] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Proteolytic enzymes are synthesized as inactive precursors, or "zymogens," to prevent unwanted protein degradation, and to enable spatial and temporal regulation of proteolytic activity. Upon sorting or appropriate compartmentalization, zymogen conversion to the active enzyme typically involves limited proteolysis and removal of an "activation segment." The sizes of activation segments range from dipeptide units to independently folding domains comprising more than 100 residues. A common form of the activation segment is an N-terminal extension of the mature enzyme, or "prosegment," that sterically blocks the active site, and thereby prevents binding of substrates. In addition to their inhibitory role, prosegments are frequently important for the folding, stability, and/or intracellular sorting of the zymogen. The mechanisms of conversion to active enzymes are diverse in nature, ranging from enzymatic or nonenzymatic cofactors that trigger activation, to a simple change in pH that results in conversion by an autocatalytic mechanism. Recent X-ray crystallographic studies of zymogens and comparisons with their active counterparts have identified the structural changes that accompany conversion. This review will focus upon the structural basis for inhibition by activation segments, as well as the molecular events that lead to the conversion of zymogens to active enzymes.
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Affiliation(s)
- A R Khan
- Department of Biochemistry, University of Alberta, Edmonton, Canada
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Gomis-Rüth FX, Gómez-Ortiz M, Vendrell J, Ventura S, Bode W, Huber R, Avilés FX. Crystal structure of an oligomer of proteolytic zymogens: detailed conformational analysis of the bovine ternary complex and implications for their activation. J Mol Biol 1997; 269:861-80. [PMID: 9223647 DOI: 10.1006/jmbi.1997.1040] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The pancreas of ruminants secretes a 100 kDa non-covalent ternary complex of the zymogen of a metalloexopeptidase, carboxypeptidase A, and the proforms of two serine endopeptidases, chymotrypsin C and proteinase E. The crystal structure of the bovine complex has been solved and refined to an R-factor of 0.192 using synchrotron radiation X-ray data to 2.35 A resolution. In this heterotrimeric complex, the 403 residue procarboxypeptidase A takes a central position, with chymotrypsinogen C and proproteinase E attached to different surface sites of it. The procarboxypeptidase A subunit is composed of the active enzyme part and the 94 residue prodomain, similar to the monomeric porcine homologous form. The 251 residue subunit chymotrypsinogen structure, the first solved of an anionic (acidic pI) chymotrypsinogen, exhibits characteristics of both chymotrypsinogen A and elastases, with a potential specificity pocket of intermediate size (to accommodate apolar medium-sized residues) although not properly folded, as in bovine chymotrypsinogen A; this pocket displays a "zymogen triad" characteristic for zymogens of the chymotrypsinogen family, consisting of three non-catalytic residues (one serine, one histidine, and one aspartate) arranged in a fashion similar to the catalytic residues in the active enzymes. Following the traits of this family, the N terminus is clamped to the main molecular body by a disulphide bond, but the close six residue activation segment is completely disordered. The third zymogen, the 253 residue proproteinase E, bears close conformational resemblance to active porcine pancreatic elastase; its specificity pocket is buried, displaying the second "zymogen triad". Its five N-terminal residues are disordered, although the close activation site is fixed to the molecular surface. The structure of this native zymogen displays large conformational differences when compared with the recently solved crystal structure of bovine subunit III, an N-terminally truncated, non-activatable, proproteinase E variant lacking the first 13 residues of the native proenzyme. Most of the prosegment of procarboxypeptidase A and its activation sites are buried in the centre of the oligomer, whilst the activation sites of chymotrypsinogen C and proproteinase E are surface-located and not involved in intra or inter-trimer contacts. This organization confers a functional role to the oligomeric structure, establishing a sequential proteolytic activation for the different zymogens of the complex. The large surface and number of residues involved in the contacts among subunits, as well as the variety of non-bonded interactions, account for the high stability of the native ternary complex.
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Affiliation(s)
- F X Gomis-Rüth
- Institut de Biologia Fonamental i Departament de Bioquímica i BiologiaMolecular, Universitat Autònoma de Barcelona, Bellaterra, Spain.
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Gomis-Rüth FX, Gómez M, Ventura S, Vendrell J, Avilés FX. Crystallization and preliminary X-ray analysis of the ternary complex of procarboxypeptidase A from bovine pancreas. FEBS Lett 1995; 367:211-3. [PMID: 7607308 DOI: 10.1016/0014-5793(95)00533-f] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The ternary complex of procarboxypeptidase A, chymotrypsinogen C and proproteinase E from bovine pancreas has been crystallized using the sitting drop vapour diffusion method. The success in obtaining crystals has been found to be critically dependent on the prevention of autolysis of the complex. In preliminary stages, crystals twinned by merohedry were obtained from a solution containing MgCl2 and polyethylenglycol 400 as precipitating agent. Later on, untwinned ones could be grown employing CaCl2 instead of MgCl2. These latter crystals belong to the rhombohedral system and to the spacegroup R3 with cell dimensions a = b = 188.5 A and c = 82.5 A. Consideration of the possible values of Vm accounts for the presence of one ternary complex molecule-oligomere per asymmetric unit. The crystals diffract beyond 2.6 A resolution and are suitable for X-ray analysis.
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Affiliation(s)
- F X Gomis-Rüth
- Institut de Biologia Fonamental, Facultat de Ciències, Universitat Autònoma de Barcelona, Bellaterra, Spain
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Oppezzo O, Ventura S, Bergman T, Vendrell J, Jörnvall H, Avilés FX. Procarboxypeptidase in rat pancreas. Overall characterization and comparison of the activation processes. EUROPEAN JOURNAL OF BIOCHEMISTRY 1994; 222:55-63. [PMID: 8200353 DOI: 10.1111/j.1432-1033.1994.tb18841.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Three monomeric procarboxypeptidases and a binary complex consisting of a procarboxypeptidase and a chymotrypsinogen have been isolated from rat pancreas by HPLC. N-terminal sequence determination, substrate-specificity analysis and physico-chemical characterization showed that the carboxypeptidase precursors were the A1, A2 and B forms. No isomorphism could be detected for any of these proenzymes and no clear evidence was obtained for the presence of procarboxypeptidase-containing quaternary complexes of the types previously described for other species. Instead, we observed the presence of a binary complex between procarboxypeptidase A2 and chymotrypsinogen B. Among the major pancreatic endoproteinases, only trypsin was found to be a general activator of rat procarboxypeptidases in vitro. Time-course analysis of the products generated after trypsin addition confirmed that full activation of procarboxypeptidase A1 requires several cleavages in the C-terminal region (residues 87-94) of the activation segment, while procarboxypeptidases A2 and B require a single cleavage each. The carboxypeptidases released participate in the trimming of the activation segment in A1 and B, but not in A2, probably because of the high specificity of the latter in the active form.
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Affiliation(s)
- O Oppezzo
- Institut de Biologia Fonamental, Universitat Autònoma de Barcelona, Spain
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Le Huerou-Luron I, Lhoste E, Wicker-Planquart C, Dakka N, Toullec R, Corring T, Guilloteau P, Puigserver A. Molecular aspects of enzyme synthesis in the exocrine pancreas with emphasis on development and nutritional regulation. Proc Nutr Soc 1993; 52:301-13. [PMID: 8234352 DOI: 10.1079/pns19930066] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
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10
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Avilés FX, Vendrell J, Guasch A, Coll M, Huber R. Advances in metallo-procarboxypeptidases. Emerging details on the inhibition mechanism and on the activation process. EUROPEAN JOURNAL OF BIOCHEMISTRY 1993; 211:381-9. [PMID: 8436102 DOI: 10.1111/j.1432-1033.1993.tb17561.x] [Citation(s) in RCA: 67] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Our knowledge on the structure and functionality of pancreatic carboxypeptidases is rapidly expanding to include that of their zymogen forms. The recent application of fast and mild isolation procedures, together with modern molecular genetic and biochemical-biophysical characterization approaches, has provided a clearer view of the basic structures and functional states in which these zymogens occur, and their evolutionary relationships. The same holds for related metallo-carboxypeptidases, either in the pro or active forms, that have been isolated and characterized in non-digestive fluids and tissues, where they probably play an important role in protein and peptide processing. The determination of the three-dimensional structure of the A and B pancreatic zymogens has revealed the molecular determinants of their inactivity and proteolytic activation. The folding of their 95-residue activation segment in a globular N-terminal domain (74-81 residues) and in a connecting region (20-14 residues), and the specific contacts of these pieces with the substrate binding sites of the enzyme, are important factors in zymogen inhibition. On the other hand, the different length of the alpha-helical connecting region and the stability of its contacts with the enzyme account for the different activation properties of A and B zymogens.
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Affiliation(s)
- F X Avilés
- Departament de Bioquímica (Fac. Ciències), Universitat Autònoma de Barcelona, Spain
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Figarella C. What is human pancreatic proelastase 1? INTERNATIONAL JOURNAL OF PANCREATOLOGY : OFFICIAL JOURNAL OF THE INTERNATIONAL ASSOCIATION OF PANCREATOLOGY 1992; 11:213-5. [PMID: 1517661 DOI: 10.1007/bf02924189] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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12
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Guasch A, Coll M, Avilés FX, Huber R. Three-dimensional structure of porcine pancreatic procarboxypeptidase A. A comparison of the A and B zymogens and their determinants for inhibition and activation. J Mol Biol 1992; 224:141-57. [PMID: 1548696 DOI: 10.1016/0022-2836(92)90581-4] [Citation(s) in RCA: 89] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The three-dimensional structure of procarboxypeptidase A (PCPA) from porcine pancreas has been determined at 2 A resolution and refined to a crystallographic R-factor of 0.198, with a root-mean-square deviation from ideal values for bond lengths of 0.015 A and for angles of 2.1 degrees. It is compared with procarboxypeptidase B (PCPB) from the same tissue. The 94/95 residue activation segments of PCPA/PCPB have equivalent folds: an N-terminal globular region with an open sandwich antiparallel alpha/antiparallel beta topology, followed by an extended alpha-helical segment, the connection to the enzyme. Alignment of the secondary structures of the activation segments of PCPA and PCPB (residues A1 to A99) indicates a two residue insertion between residues A34 and A35 and a C-terminal helix that is two turns longer in PCPA compared to PCPB. A deletion is observed between residues A43 to A45, the region containing the short 3(10) helix that covers the active site in PCPB. The globular region (A4 to A80) shields the preformed active center of carboxypeptidase A (CPA), but none of the residues involved in catalysis makes direct contacts with the activation segment. In contrast, subsites S2, S3 and S4 of the enzyme, involved in the binding of peptidic substrates, are blocked by specific contacts with residues AspA36, TrpA38, ArgA47, AspA53 and GluA86 of the activation segment. It has been described that several residues of CPA exhibit different conformations in the free enzyme compared to when substrate is bound: Arg127, Arg145, Glu270 and Tyr248. In PCPA all of these residues are found in the "active" conformation, as if substrate were actually bound. The presence of a ligand, tentatively interpreted as a free amino acid (Val) in the active center could explain this fact. The connecting region (A80 to A99), the target for proteolytic activation, establishes fewer contacts with the enzyme in PCPA than in PCPB. The activation segment of PCPA (A4 to A99) remains bound to the enzyme after the first trypsin cleavage between ArgA99-Ala1 probably due to the stability conferred on it by the alpha-helix (alpha 3) of the connecting segment. These and other structural features may explain the differences in intrinsic activity and different rates or proteolytic activation of each zymogen.
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Affiliation(s)
- A Guasch
- Max-Planck-Institut für Biochemie, Martinsried bei München, Germany
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