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Dubey A, Baxter M, Hendargo KJ, Medrano-Soto A, Saier MH. The Pentameric Ligand-Gated Ion Channel Family: A New Member of the Voltage Gated Ion Channel Superfamily? Int J Mol Sci 2024; 25:5005. [PMID: 38732224 PMCID: PMC11084639 DOI: 10.3390/ijms25095005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2024] [Revised: 04/28/2024] [Accepted: 04/29/2024] [Indexed: 05/13/2024] Open
Abstract
In this report we present seven lines of bioinformatic evidence supporting the conclusion that the Pentameric Ligand-gated Ion Channel (pLIC) Family is a member of the Voltage-gated Ion Channel (VIC) Superfamily. In our approach, we used the Transporter Classification Database (TCDB) as a reference and applied a series of bioinformatic methods to search for similarities between the pLIC family and members of the VIC superfamily. These include: (1) sequence similarity, (2) compatibility of topology and hydropathy profiles, (3) shared domains, (4) conserved motifs, (5) similarity of Hidden Markov Model profiles between families, (6) common 3D structural folds, and (7) clustering analysis of all families. Furthermore, sequence and structural comparisons as well as the identification of a 3-TMS repeat unit in the VIC superfamily suggests that the sixth transmembrane segment evolved into a re-entrant loop. This evidence suggests that the voltage-sensor domain and the channel domain have a common origin. The classification of the pLIC family within the VIC superfamily sheds light onto the topological origins of this family and its evolution, which will facilitate experimental verification and further research into this superfamily by the scientific community.
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Affiliation(s)
| | | | | | - Arturo Medrano-Soto
- Department of Molecular Biology, School of Biological Sciences, University of California San Diego, La Jolla, CA 92093-0116, USA; (A.D.); (M.B.); (K.J.H.)
| | - Milton H. Saier
- Department of Molecular Biology, School of Biological Sciences, University of California San Diego, La Jolla, CA 92093-0116, USA; (A.D.); (M.B.); (K.J.H.)
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2
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Boros E, Sebák F, Héja D, Szakács D, Zboray K, Schlosser G, Micsonai A, Kardos J, Bodor A, Pál G. Directed Evolution of Canonical Loops and Their Swapping between Unrelated Serine Proteinase Inhibitors Disprove the Interscaffolding Additivity Model. J Mol Biol 2019; 431:557-575. [PMID: 30543823 DOI: 10.1016/j.jmb.2018.12.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2018] [Revised: 11/26/2018] [Accepted: 12/06/2018] [Indexed: 11/26/2022]
Abstract
Reversible serine proteinase inhibitors comprise 18 unrelated families. Each family has a distinct representative structure but contains a surface loop that adopts the same, canonical conformation in the enzyme-inhibitor complex. The Laskowski mechanism universally applies for the action of all canonical inhibitors independent of their scaffold, but it has two nontrivial extrapolations. Intrascaffolding additivity states that all enzyme-contacting loop residues act independently of each other, while interscaffolding additivity claims that these residues act independently of the scaffold. These theories have great importance for engineering proteinase inhibitors but have not been comprehensively challenged. Therefore, we tested the interscaffolding additivity theory by hard-randomizing all enzyme-contacting canonical loop positions of a Kazal- and a Pacifastin-scaffold inhibitor, displaying the variants on M13 phage, and selecting the libraries on trypsin and chymotrypsin. Directed evolution delivered different patterns on both scaffolds against both enzymes, which contradicts interscaffolding additivity. To quantitatively assess the extent of non-additivity, we measured the affinities of the optimal binding loop variants and their binding loop-swapped versions. While optimal variants have picomolar affinities, swapping the evolved loops results in up to 200,000-fold affinity loss. To decipher the underlying causes, we characterized the stability, overall structure and dynamics of the inhibitors with differential scanning calorimetry, circular dichroism and NMR spectroscopy and molecular dynamic simulations. These studies revealed that the foreign loop destabilizes the lower-stability Pacifastin scaffold, while the higher-stability Kazal scaffold distorts the foreign loop. Our findings disprove interscaffolding additivity and show that loop and scaffold form one integrated unit that needs to be coevolved to provide high-affinity inhibition.
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Affiliation(s)
- Eszter Boros
- Department of Biochemistry, ELTE Eötvös Loránd University, Pázmány Péter sétány 1/C, H-1117 Budapest, Hungary
| | - Fanni Sebák
- Laboratory of Structural Chemistry and Biology, Institute of Chemistry, ELTE Eötvös Loránd University, Pázmány Péter sétány 1/A, H-1117 Budapest, Hungary; Doctoral School of Pharmaceutical Sciences, Semmelweis University, Üllői út 26, H-1085 Budapest, Hungary
| | - Dávid Héja
- Department of Biochemistry, ELTE Eötvös Loránd University, Pázmány Péter sétány 1/C, H-1117 Budapest, Hungary
| | - Dávid Szakács
- Department of Biochemistry, ELTE Eötvös Loránd University, Pázmány Péter sétány 1/C, H-1117 Budapest, Hungary
| | - Katalin Zboray
- Department of Biochemistry, ELTE Eötvös Loránd University, Pázmány Péter sétány 1/C, H-1117 Budapest, Hungary
| | - Gitta Schlosser
- Department of Analytical Chemistry, Institute of Chemistry, ELTE Eötvös Loránd University, Pázmány Péter sétány 1/A, H-1117 Budapest, Hungary
| | - András Micsonai
- Department of Biochemistry, ELTE Eötvös Loránd University, Pázmány Péter sétány 1/C, H-1117 Budapest, Hungary
| | - József Kardos
- Department of Biochemistry, ELTE Eötvös Loránd University, Pázmány Péter sétány 1/C, H-1117 Budapest, Hungary
| | - Andrea Bodor
- Laboratory of Structural Chemistry and Biology, Institute of Chemistry, ELTE Eötvös Loránd University, Pázmány Péter sétány 1/A, H-1117 Budapest, Hungary
| | - Gábor Pál
- Department of Biochemistry, ELTE Eötvös Loránd University, Pázmány Péter sétány 1/C, H-1117 Budapest, Hungary.
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3
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Ramesh K, Lama D, Tan KW, Nguyen VS, Chew FT, Verma CS, Mok YK. Homologous Lympho-Epithelial Kazal-type Inhibitor Domains Delay Blood Coagulation by Inhibiting Factor X and XI with Differential Specificity. Structure 2018; 26:1178-1186.e3. [PMID: 30017565 DOI: 10.1016/j.str.2018.05.018] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2018] [Revised: 04/30/2018] [Accepted: 05/29/2018] [Indexed: 10/28/2022]
Abstract
Despite being initially identified in the blood filtrate, LEKTI is a 15-domain Kazal-type inhibitor mostly known in the regulation of skin desquamation. In the current study, screening of serine proteases in blood coagulation cascade showed that LEKTI domain 4 has inhibitory activity toward only FXIa, whereas LEKTI domain 6 inhibits both FXIa and FXaB (bovine FXa). Nuclear magnetic resonance structural and dynamic experiments plus molecular dynamics simulation revealed that LEKTI domain 4 has enhanced backbone flexibility at the reactive-site loop. A model of the LEKTI-protease complex revealed that FXaB has a narrower S4 pocket compared with FXIa and hence prefers only small side-chain residues at the P4 position, such as Ala in LEKTI domain 6. Mutational studies combined with a molecular complex model suggest that both a more flexible reactive-site loop and a bulky residue at the P4 position make LEKTI domain 4 a weaker but highly selective inhibitor of FXIa.
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Affiliation(s)
- Karthik Ramesh
- Department of Biological Sciences, National University of Singapore, 16 Science Drive 4, Singapore 117558, Singapore
| | - Dilraj Lama
- Bioinformatics Institute, A(∗)STAR (Agency for Science, Technology and Research), 30 Biopolis Street, #07-01 Matrix, Singapore 138671, Singapore
| | - Kang Wei Tan
- Department of Biological Sciences, National University of Singapore, 16 Science Drive 4, Singapore 117558, Singapore
| | - Van Sang Nguyen
- Department of Biological Sciences, National University of Singapore, 16 Science Drive 4, Singapore 117558, Singapore
| | - Fook Tim Chew
- Department of Biological Sciences, National University of Singapore, 16 Science Drive 4, Singapore 117558, Singapore
| | - Chandra S Verma
- Department of Biological Sciences, National University of Singapore, 16 Science Drive 4, Singapore 117558, Singapore; Bioinformatics Institute, A(∗)STAR (Agency for Science, Technology and Research), 30 Biopolis Street, #07-01 Matrix, Singapore 138671, Singapore; School of Biological Sciences, Nanyang Technological University, 50 Nanyang Drive, Singapore 637551, Singapore.
| | - Yu Keung Mok
- Department of Biological Sciences, National University of Singapore, 16 Science Drive 4, Singapore 117558, Singapore.
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4
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Masurier N, Arama DP, El Amri C, Lisowski V. Inhibitors of kallikrein-related peptidases: An overview. Med Res Rev 2017; 38:655-683. [DOI: 10.1002/med.21451] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2017] [Revised: 04/24/2017] [Accepted: 05/16/2017] [Indexed: 12/11/2022]
Affiliation(s)
- Nicolas Masurier
- Institut des Biomolécules Max Mousseron, UMR 5247, CNRS; Université de Montpellier, ENSCM, UFR des Sciences Pharmaceutiques et Biologiques; Montpellier Cedex France
| | - Dominique P. Arama
- Institut des Biomolécules Max Mousseron, UMR 5247, CNRS; Université de Montpellier, ENSCM, UFR des Sciences Pharmaceutiques et Biologiques; Montpellier Cedex France
| | - Chahrazade El Amri
- Sorbonne Universités, UPMC Univ Paris 06, UMR 8256; Biological Adaptation and Ageing, Integrated Cellular Ageing and Inflammation, Molecular & Functional Enzymology; Paris France
| | - Vincent Lisowski
- Institut des Biomolécules Max Mousseron, UMR 5247, CNRS; Université de Montpellier, ENSCM, UFR des Sciences Pharmaceutiques et Biologiques; Montpellier Cedex France
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5
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Sarri CA, Roussaki-Schulze A, Vasilopoulos Y, Zafiriou E, Patsatsi A, Stamatis C, Gidarokosta P, Sotiriadis D, Sarafidou T, Mamuris Z. Netherton Syndrome: A Genotype-Phenotype Review. Mol Diagn Ther 2016; 21:137-152. [DOI: 10.1007/s40291-016-0243-y] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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6
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Jefferson T, Auf dem Keller U, Bellac C, Metz VV, Broder C, Hedrich J, Ohler A, Maier W, Magdolen V, Sterchi E, Bond JS, Jayakumar A, Traupe H, Chalaris A, Rose-John S, Pietrzik CU, Postina R, Overall CM, Becker-Pauly C. The substrate degradome of meprin metalloproteases reveals an unexpected proteolytic link between meprin β and ADAM10. Cell Mol Life Sci 2012; 70:309-33. [PMID: 22940918 PMCID: PMC3535375 DOI: 10.1007/s00018-012-1106-2] [Citation(s) in RCA: 100] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2012] [Revised: 07/19/2012] [Accepted: 07/23/2012] [Indexed: 01/10/2023]
Abstract
The in vivo roles of meprin metalloproteases in pathophysiological conditions remain elusive. Substrates define protease roles. Therefore, to identify natural substrates for human meprin α and β we employed TAILS (terminal amine isotopic labeling of substrates), a proteomics approach that enriches for N-terminal peptides of proteins and cleavage fragments. Of the 151 new extracellular substrates we identified, it was notable that ADAM10 (a disintegrin and metalloprotease domain-containing protein 10)-the constitutive α-secretase-is activated by meprin β through cleavage of the propeptide. To validate this cleavage event, we expressed recombinant proADAM10 and after preincubation with meprin β, this resulted in significantly elevated ADAM10 activity. Cellular expression in murine primary fibroblasts confirmed activation. Other novel substrates including extracellular matrix proteins, growth factors and inhibitors were validated by western analyses and enzyme activity assays with Edman sequencing confirming the exact cleavage sites identified by TAILS. Cleavages in vivo were confirmed by comparing wild-type and meprin(-/-) mice. Our finding of cystatin C, elafin and fetuin-A as substrates and natural inhibitors for meprins reveal new mechanisms in the regulation of protease activity important for understanding pathophysiological processes.
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Affiliation(s)
- Tamara Jefferson
- Institute of Biochemistry, Christian-Albrechts-University, 24118, Kiel, Germany
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7
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Fortugno P, Bresciani A, Paolini C, Pazzagli C, El Hachem M, D'Alessio M, Zambruno G. Proteolytic activation cascade of the Netherton syndrome-defective protein, LEKTI, in the epidermis: implications for skin homeostasis. J Invest Dermatol 2011; 131:2223-32. [PMID: 21697885 DOI: 10.1038/jid.2011.174] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Lympho-epithelial Kazal-type-related inhibitor (LEKTI) is the defective protein of the ichthyosiform condition Netherton syndrome (NS). Strongly expressed in the most differentiated epidermal layers, LEKTI is a serine protease inhibitor synthesized as three different high-molecular-weight precursors, which are rapidly processed into shorter fragments and secreted extracellularly. LEKTI polypeptides interact with several proteases to regulate skin barrier homeostasis as well as inflammatory and/or immunoallergic responses. Here, by combining antibody mapping, N-terminal sequencing, and site-specific mutagenesis, we defined the amino-acid sequence of most of the LEKTI polypeptides physiologically generated in human epidermis. We also identified three processing intermediates not described so far. Hence, a proteolytic cascade model for LEKTI activation is proposed. We then pinpointed the most effective fragments against the desquamation-related kallikreins (KLKs) and we proved that LEKTI is involved in stratum corneum shedding as some of its polypeptides inhibit the KLK-mediated proteolysis of desmoglein-1. Finally, we quantified the individual LEKTI fragments in the uppermost epidermis, showing that the ratios between LEKTI polypeptides and active KLK5 are compatible with a fine-tuned inhibition. These findings are relevant both to the understanding of skin homeostasis regulation and to the design of novel therapeutic strategies for NS.
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Affiliation(s)
- Paola Fortugno
- Laboratory of Molecular and Cell Biology, Istituto Dermopatico dell'Immacolata IDI-IRCCS, Rome, Italy.
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8
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Horita S, Ishibashi J, Nagata K, Miyakawa T, Yamakawa M, Tanokura M. Isolation, cDNA cloning, and structure-based functional characterization of oryctin, a hemolymph protein from the coconut rhinoceros beetle, Oryctes rhinoceros, as a novel serine protease inhibitor. J Biol Chem 2010; 285:30150-8. [PMID: 20630859 DOI: 10.1074/jbc.m110.124735] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
We isolated oryctin, a 66-residue peptide, from the hemolymph of the coconut rhinoceros beetle Oryctes rhinoceros and cloned its cDNA. Oryctin is dissimilar to any other known peptides in amino acid sequence, and its function has been unknown. To reveal that function, we determined the solution structure of recombinant (13)C,(15)N-labeled oryctin by heteronuclear NMR spectroscopy. Oryctin exhibits a fold similar to that of Kazal-type serine protease inhibitors but has a unique additional C-terminal α-helix. We performed protease inhibition assays of oryctin against several bacterial and eukaryotic proteases. Oryctin does inhibit the following serine proteases: α-chymotrypsin, endopeptidase K, subtilisin Carlsberg, and leukocyte elastase, with K(i) values of 3.9 × 10(-10) m, 6.2 × 10(-10) m, 1.4 × 10(-9) m, and 1.2 × 10(-8) m, respectively. Although the target molecule of oryctin in the beetle hemolymph remains obscure, our results showed that oryctin is a novel single domain Kazal-type inhibitor and could play a key role in protecting against bacterial infections.
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Affiliation(s)
- Shoichiro Horita
- From the Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan
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9
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Goettig P, Magdolen V, Brandstetter H. Natural and synthetic inhibitors of kallikrein-related peptidases (KLKs). Biochimie 2010; 92:1546-67. [PMID: 20615447 PMCID: PMC3014083 DOI: 10.1016/j.biochi.2010.06.022] [Citation(s) in RCA: 105] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2010] [Accepted: 06/29/2010] [Indexed: 01/21/2023]
Abstract
Including the true tissue kallikrein KLK1, kallikrein-related peptidases (KLKs) represent a family of fifteen mammalian serine proteases. While the physiological roles of several KLKs have been at least partially elucidated, their activation and regulation remain largely unclear. This obscurity may be related to the fact that a given KLK fulfills many different tasks in diverse fetal and adult tissues, and consequently, the timescale of some of their physiological actions varies significantly. To date, a variety of endogenous inhibitors that target distinct KLKs have been identified. Among them are the attenuating Zn(2+) ions, active site-directed proteinaceous inhibitors, such as serpins and the Kazal-type inhibitors, or the huge, unspecific compartment forming α(2)-macroglobulin. Failure of these inhibitory systems can lead to certain pathophysiological conditions. One of the most prominent examples is the Netherton syndrome, which is caused by dysfunctional domains of the Kazal-type inhibitor LEKTI-1 which fail to appropriately regulate KLKs in the skin. Small synthetic inhibitory compounds and natural polypeptidic exogenous inhibitors have been widely employed to characterize the activity and substrate specificity of KLKs and to further investigate their structures and biophysical properties. Overall, this knowledge leads not only to a better understanding of the physiological tasks of KLKs, but is also a strong fundament for the synthesis of small compound drugs and engineered biomolecules for pharmaceutical approaches. In several types of cancer, KLKs have been found to be overexpressed, which makes them clinically relevant biomarkers for prognosis and monitoring. Thus, down regulation of excessive KLK activity in cancer and in skin diseases by small inhibitor compounds may represent attractive therapeutical approaches.
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Affiliation(s)
- Peter Goettig
- Division of Structural Biology, Department of Molecular Biology, University of Salzburg, Billrothstrasse 11, 5020 Salzburg, Austria.
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10
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Vasileiou Z, Barlos KK, Gatos D, Adermann K, Deraison C, Barlos K. Synthesis of the proteinase inhibitor LEKTI domain 6 by the fragment condensation method and regioselective disulfide bond formation. Biopolymers 2010; 94:339-49. [DOI: 10.1002/bip.21376] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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11
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Wang ZH, Zhao XF, Wang JX. Characterization, kinetics, and possible function of Kazal-type proteinase inhibitors of Chinese white shrimp, Fenneropenaeus chinensis. FISH & SHELLFISH IMMUNOLOGY 2009; 26:885-897. [PMID: 19379816 DOI: 10.1016/j.fsi.2009.03.024] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2009] [Revised: 03/17/2009] [Accepted: 03/30/2009] [Indexed: 05/27/2023]
Abstract
Serine proteinase inhibitor plays an essential role in arthropods by restraining the activities of endogenic or exogenic serine proteinases. Four Kazal-type serine proteinase inhibitors, Fcspi-1-4, from the hepatopancreas of Chinese white shrimp, Fenneropenaeus chinensis, were cloned and identified. The open reading frames (ORFs) of Fcspis are 1389, 1236, 1080, and 939 base pairs, encode the pre-proteins of 462, 411, 359, and 312 amino acids and form the 9, 8, 7, and 6 typical Kazal domains, respectively. When analyzing the amino acid sequences of the four inhibitors, it was found that they might have been derived from the same transcript, which was subjected to alternative splicing, and none of the Kazal domains were identical within each inhibitor. Multiple alignments showed that the Kazal inhibitors were homologous with a conserved motif of Cx(3)Cx(6)VCGSDGxTYx(3)CxLx(5)Cx(5)ITx(6)GC. The results from RT-PCR indicated that the expression of Fcspis as a whole was upregulated by bacterial challenge, no obvious change was noticed after viral challenge, and Fcspi-1 had a similar expression pattern with that of Fcspis. Recombinant FcSPIs were successfully expressed in bacteria and purified for further study. Recombinant FcSPI-1 was sensitive to DTT and had thermal stability. The inhibitory kinetics assay suggested that rFcSPI-1 was a mixed-type fast tight binding inhibitor with inhibitory activities against subtilisin A at a molar ratio of 1:1, 1:2 against proteinase K, and 2:1 against elastase. It can firmly bound to two Gram-positive and one Gram-negative bacteria but without anti-bacterial ability. In addition, it inhibited the activities of both bacterial-secreted proteinases and natural chymotrypsin of Chinese white shrimp, suggesting that FcSPI-1 may participate in the immune defence response by inhibition of bacterial pathogen proteinases and possibly be involved in the regulation of shrimp proteinase activity.
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Affiliation(s)
- Zong-Heng Wang
- School of Life Sciences, Shandong University, Jinan 250100, China
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12
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Donpudsa S, Tassanakajon A, Rimphanitchayakit V. Domain inhibitory and bacteriostatic activities of the five-domain Kazal-type serine proteinase inhibitor from black tiger shrimp Penaeus monodon. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2009; 33:481-488. [PMID: 18930077 DOI: 10.1016/j.dci.2008.09.009] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/20/2008] [Revised: 09/15/2008] [Accepted: 09/18/2008] [Indexed: 05/26/2023]
Abstract
Serine proteinase inhibitors (SPIs) in multi-cellular organisms are important modulators of proteinase activities in various biological processes. A five-domain Kazal-type SPI SPIPm2 from the black tiger shrimp Penaeus monodon is presumably involved in innate immune response. The SPIPm2 with the domain P1 residues T, A, E, K and E was isolated from the hemocyte cDNA libraries and found to strongly inhibit subtilisin and elastase, and weakly inhibit trypsin. To unravel further the inhibitory activity of each domain, we subcloned, over-expressed and purified each individual SPI domain. Their inhibitory specificities against trypsin, subtilisin and elastase were determined. Domain 1 was found to be inactive. Domains 2, 3 and 5 inhibited subtilisin. Domain 2 inhibited also elastase. Domain 4 weakly inhibited subtilisin and trypsin. The intact SPIPm2 inhibitor was found to possess bacteriostatic activity against the Bacillus subtilis but not the Bacillus megaterium, Staphylococcus aureus, Vibrio harveyi 639 and Escherichia coli JM109. Domains 2, 4 and 5 contributed to this bacteriostatic activity.
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Affiliation(s)
- Suchao Donpudsa
- Shrimp Molecular Biology and Genomics Laboratory, Department of Biochemistry, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand
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13
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Fernández IS, Ständker L, Mägert HJ, Forssmann WG, Giménez-Gallego G, Romero A. Crystal Structure of Human Epidermal Kallikrein 7 (hK7) Synthesized Directly in its Native State in E. coli: Insights into the Atomic Basis of its Inhibition by LEKTI Domain 6 (LD6). J Mol Biol 2008; 377:1488-97. [DOI: 10.1016/j.jmb.2008.01.089] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2007] [Revised: 01/23/2008] [Accepted: 01/29/2008] [Indexed: 10/22/2022]
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14
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Transitive homology-guided structural studies lead to discovery of Cro proteins with 40% sequence identity but different folds. Proc Natl Acad Sci U S A 2008; 105:2343-8. [PMID: 18227506 DOI: 10.1073/pnas.0711589105] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Proteins that share common ancestry may differ in structure and function because of divergent evolution of their amino acid sequences. For a typical diverse protein superfamily, the properties of a few scattered members are known from experiment. A satisfying picture of functional and structural evolution in relation to sequence changes, however, may require characterization of a larger, well chosen subset. Here, we employ a "stepping-stone" method, based on transitive homology, to target sequences intermediate between two related proteins with known divergent properties. We apply the approach to the question of how new protein folds can evolve from preexisting folds and, in particular, to an evolutionary change in secondary structure and oligomeric state in the Cro family of bacteriophage transcription factors, initially identified by sequence-structure comparison of distant homologs from phages P22 and lambda. We report crystal structures of two Cro proteins, Xfaso 1 and Pfl 6, with sequences intermediate between those of P22 and lambda. The domains show 40% sequence identity but differ by switching of alpha-helix to beta-sheet in a C-terminal region spanning approximately 25 residues. Sedimentation analysis also suggests a correlation between helix-to-sheet conversion and strengthened dimerization.
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Vitzithum K, Lauber T, Kreutzmann P, Schulz A, Sommerhoff CP, Rösch P, Marx UC. LEKTI domain 15 is a functional Kazal-type proteinase inhibitor. Protein Expr Purif 2008; 57:45-56. [DOI: 10.1016/j.pep.2007.08.012] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2007] [Revised: 08/16/2007] [Accepted: 08/27/2007] [Indexed: 11/28/2022]
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16
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Emami N, Diamandis EP. New insights into the functional mechanisms and clinical applications of the kallikrein-related peptidase family. Mol Oncol 2007; 1:269-87. [PMID: 19383303 DOI: 10.1016/j.molonc.2007.09.003] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2007] [Revised: 09/04/2007] [Accepted: 09/07/2007] [Indexed: 11/28/2022] Open
Abstract
The Kallikrein-related peptidase (KLK) family consists of fifteen conserved serine proteases that form the largest contiguous cluster of proteases in the human genome. While primarily recognized for their clinical utilities as potential disease biomarkers, new compelling evidence suggests that this family plays a significant role in various physiological processes, including skin desquamation, semen liquefaction, neural plasticity, and body fluid homeostasis. KLK activation is believed to be mediated through highly organized proteolytic cascades, regulated through a series of feedback loops, inhibitors, auto-degradation and internal cleavages. Gene expression is mainly hormone-dependent, even though transcriptional epigenetic regulation has also been reported. These regulatory mechanisms are integrated with various signaling pathways to mediate multiple functions. Dysregulation of these pathways has been implicated in a large number of neoplastic and non-neoplastic pathological conditions. This review highlights our current knowledge of structural/phylogenetic features, functional role and regulatory/signaling mechanisms of this important family of enzymes.
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Affiliation(s)
- Nashmil Emami
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada
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Deraison C, Bonnart C, Lopez F, Besson C, Robinson R, Jayakumar A, Wagberg F, Brattsand M, Hachem JP, Leonardsson G, Hovnanian A. LEKTI fragments specifically inhibit KLK5, KLK7, and KLK14 and control desquamation through a pH-dependent interaction. Mol Biol Cell 2007; 18:3607-19. [PMID: 17596512 PMCID: PMC1951746 DOI: 10.1091/mbc.e07-02-0124] [Citation(s) in RCA: 216] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2007] [Revised: 06/11/2007] [Accepted: 06/18/2007] [Indexed: 11/11/2022] Open
Abstract
LEKTI is a 15-domain serine proteinase inhibitor whose defective expression underlies the severe autosomal recessive ichthyosiform skin disease, Netherton syndrome. Here, we show that LEKTI is produced as a precursor rapidly cleaved by furin, generating a variety of single or multidomain LEKTI fragments secreted in cultured keratinocytes and in the epidermis. The identity of these biological fragments (D1, D5, D6, D8-D11, and D9-D15) was inferred from biochemical analysis, using a panel of LEKTI antibodies. The functional inhibitory capacity of each fragment was tested on a panel of serine proteases. All LEKTI fragments, except D1, showed specific and differential inhibition of human kallikreins 5, 7, and 14. The strongest inhibition was observed with D8-D11, toward KLK5. Kinetics analysis revealed that this interaction is rapid and irreversible, reflecting an extremely tight binding complex. We demonstrated that pH variations govern this interaction, leading to the release of active KLK5 from the complex at acidic pH. These results identify KLK5, a key actor of the desquamation process, as the major target of LEKTI. They disclose a new mechanism of skin homeostasis by which the epidermal pH gradient allows precisely regulated KLK5 activity and corneodesmosomal cleavage in the most superficial layers of the stratum corneum.
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Affiliation(s)
- Celine Deraison
- *Institut National de la Santé et de la Recherche Médicale, U563, Toulouse, F-31300 France
- Université Toulouse III Paul-Sabatier, Unité Mixte de Recherche-S563, Toulouse, F-31400 France
- Centre Hospitalier Universitaire de Toulouse, Hopital Purpan, Departement de Génétique Médicale, Toulouse, F-31000 France
| | - Chrystelle Bonnart
- *Institut National de la Santé et de la Recherche Médicale, U563, Toulouse, F-31300 France
- Université Toulouse III Paul-Sabatier, Unité Mixte de Recherche-S563, Toulouse, F-31400 France
| | - Frederic Lopez
- Université Toulouse III Paul-Sabatier, Faculté de Médecine Toulouse-Rangueil, Institut Louis Bugnard (IFR31), Toulouse, F-31400 France
| | - Celine Besson
- *Institut National de la Santé et de la Recherche Médicale, U563, Toulouse, F-31300 France
- Université Toulouse III Paul-Sabatier, Unité Mixte de Recherche-S563, Toulouse, F-31400 France
| | - Ross Robinson
- Wellcome Trust Centre for Human Genetics, Oxford OX3 7BN, United Kingdom
| | - Arumugam Jayakumar
- Department of Head and Neck Surgery, M. D. Anderson Cancer Center, Houston, TX 77030
| | | | - Maria Brattsand
- **Department of Public Health and Clinical Medicine, Section for Dermatology and Venereology, Umeå University, SE-901 87 Umeå, Sweden; and
| | - Jean Pierre Hachem
- Department of Dermatology, Vrije Universiteit Brussels, 1090 Brussels, Belgium
| | | | - Alain Hovnanian
- *Institut National de la Santé et de la Recherche Médicale, U563, Toulouse, F-31300 France
- Université Toulouse III Paul-Sabatier, Unité Mixte de Recherche-S563, Toulouse, F-31400 France
- Centre Hospitalier Universitaire de Toulouse, Hopital Purpan, Departement de Génétique Médicale, Toulouse, F-31000 France
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Brillard-Bourdet M, Hamdaoui A, Hajjar E, Boudier C, Reuter N, Ehret-Sabatier L, Bieth J, Gauthier F. A novel locust (Schistocerca gregaria) serine protease inhibitor with a high affinity for neutrophil elastase. Biochem J 2006; 400:467-76. [PMID: 16839309 PMCID: PMC1698593 DOI: 10.1042/bj20060437] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
We have purified to homogeneity two forms of a new serine protease inhibitor specific for elastase/chymotrypsin from the ovary gland of the desert locust Schistocerca gregaria. This protein, greglin, has 83 amino acid residues and bears putative phosphorylation sites. Amino acid sequence alignments revealed no homology with pacifastin insect inhibitors and only a distant relationship with Kazal-type inhibitors. This was confirmed by computer-based structural studies. The most closely related homologue is a putative gene product from Ciona intestinalis with which it shares 38% sequence homology. Greglin is a fast-acting and tight binding inhibitor of human neutrophil elastase (k(ass)=1.2x10(7) M(-1) x s(-1), K(i)=3.6 nM) and subtilisin. It also binds neutrophil cathepsin G, pancreatic elastase and chymotrypsin with a lower affinity (26 nM< or =K(i)< or =153 nM), but does not inhibit neutrophil protease 3 or pancreatic trypsin. The capacity of greglin to inhibit neutrophil elastase was not significantly affected by exposure to acetonitrile, high temperature (90 degrees C), low or high pH (2.5-11.0), N-chlorosuccinimide-mediated oxidation or the proteolytic enzymes trypsin, papain and pseudolysin from Pseudomonas aeruginosa. Greglin efficiently inhibits the neutrophil elastase activity of sputum supernatants from cystic fibrosis patients. Its biological function in the locust ovary gland is currently unknown, but its physicochemical properties suggest that it can be used as a template to design a new generation of highly resistant elastase inhibitors for treating inflammatory diseases.
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Affiliation(s)
| | - Ahmed Hamdaoui
- ‡Université Cadi Ayyad, Faculté des Sciences Semlalia, Marrakech, Morocco
- §INSERM U392, Université Louis Pasteur, Strasbourg I, F-67401 Illkirch, France
| | - Eric Hajjar
- ∥Computational Biology Unit, BCCS, University of Bergen, N-5008 Bergen, Norway
| | - Christian Boudier
- ¶CNRS UMR 7175, Université Louis Pasteur, Strasbourg I, F-67401 Illkirch, France
| | - Nathalie Reuter
- ∥Computational Biology Unit, BCCS, University of Bergen, N-5008 Bergen, Norway
| | | | - Joseph G. Bieth
- §INSERM U392, Université Louis Pasteur, Strasbourg I, F-67401 Illkirch, France
| | - Francis Gauthier
- *INSERM U618, F-37000 Tours, France
- †Université François Rabelais, F-37000 Tours, France
- To whom correspondence should be addressed, at INSERM U618 ‘Protéases et Vectorisation Pulmonaires’, Université François Rabelais, 10 Bd Tonnellé, 37032 Tours Cedex, France (email )
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19
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Schechter NM, Choi EJ, Wang ZM, Hanakawa Y, Stanley JR, Kang Y, Clayman GL, Jayakumar A. Inhibition of human kallikreins 5 and 7 by the serine protease inhibitor lympho-epithelial Kazal-type inhibitor (LEKTI). Biol Chem 2005; 386:1173-84. [PMID: 16307483 DOI: 10.1515/bc.2005.134] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
AbstractLEKTI is a 120-kDa protein that plays an important role in skin development, as mutations affecting LEKTI synthesis underlie Netherton syndrome, an inherited skin disorder producing severe scaling. Its primary sequence indicates that the protein consists of 15 domains, all resembling a Kazal-type serine protease inhibitor. LEKTI and two serine proteases belonging to the human tissue kallikrein (hK) family (hK5 and hK7) are expressed in the granular layer of skin. In this study, we characterize the interaction of two recombinant LEKTI fragments containing three or four intact Kazal domains (domains 6–8 and 9–12) with recombinant rhK5, a trypsin-like protease, and recombinant rhK7, a chymotrypsin-like protease. Both fragments inhibited rhK5 similarly in binding and kinetic studies performed at pH 8.0, as well as pH 5.0, the pH of the stratum corneum where both LEKTI and proteases may function. Inhibition equilibrium constants (Ki) measured either directly in concentration-dependent studies or calculated from measured association (kass) and dissociation (kdis) rate constants were 1.2–5.5 nM at pH 8.0 and 10–20 nM at pH 5.0. At pH 8.0,kassandkdisvalues were 4.7×105 M−1s−1and 5.5×10−4 s−1, and at pH 5.0 they were 4.0×104 M−1 s−1and 4.3×10−4 s−1, respectively. The lowKiandkdisvalues (t1/2of 20–25 min) indicate tight and specific association. Only fragment 6–9′ was a good inhibitor of rhK7, demonstrating aKiof 11 nM at pH 8.0 in a reaction that was rapidly reversible. These results show that LEKTI, at least in fragment form, is a potent inhibitor of rhK5 and that this protease may be a target of LEKTI in human skin.
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Affiliation(s)
- Norman M Schechter
- Department of Dermatology, University of Pennsylvania, Philadelphia, PA 19104, USA.
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20
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Tian M, Kamoun S. A two disulfide bridge Kazal domain from Phytophthora exhibits stable inhibitory activity against serine proteases of the subtilisin family. BMC BIOCHEMISTRY 2005; 6:15. [PMID: 16117831 PMCID: PMC1236909 DOI: 10.1186/1471-2091-6-15] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/08/2005] [Accepted: 08/23/2005] [Indexed: 11/21/2022]
Abstract
BACKGROUND Kazal-like serine protease inhibitors are defined by a conserved sequence motif. A typical Kazal domain contains six cysteine residues leading to three disulfide bonds with a 1-5/2-4/3-6 pattern. Most Kazal domains described so far belong to this class. However, a novel class of Kazal domains with two disulfide bridges resulting from the absence of the third and sixth cysteines have been found in biologically important molecules, such as human LEKTI, a 15-domain inhibitor associated with the severe congenital disease Netherton syndrome. These domains are referred to as atypical Kazal domains. Previously, EPI1, a Kazal-like protease inhibitor from the oomycete plant pathogen Phytophthora infestans, was shown to be a tight-binding inhibitor of subtilisin A. EPI1 also inhibits and interacts with the pathogenesis-related P69B subtilase of the host plant tomato, suggesting a role in virulence. EPI1 is composed of two Kazal domains, the four-cysteine atypical domain EPI1a and the typical domain EPI1b. RESULTS In this study, we predicted the inhibition constants of EPI1a and EPI1b to subtilisin A using the additivity-based sequence to reactivity algorithm (Laskowski algorithm). The atypical domain EPI1a, but not the typical domain EPI1b, was predicted to have strong inhibitory activity against subtilisin A. Inhibition assays and coimmunoprecipitation experiments showed that recombinant domain EPI1a exhibited stable inhibitory activity against subilisin A and was solely responsible for inhibition and interaction with tomato P69B subtilase. CONCLUSION The finding that the two disulfide bridge atypical Kazal domain EPI1a is a stable inhibitor indicates that the missing two cysteines and their corresponding disulfide bond are not essential for inhibitor reactivity and stability. This report also suggests that the Laskowski algorithm originally developed and validated with typical Kazal domains might operate accurately for atypical Kazal domains.
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Affiliation(s)
- Miaoying Tian
- Department of Plant Pathology, The Ohio State University, Ohio Agricultural Research and Development Center, Wooster, OH 44691, USA
| | - Sophien Kamoun
- Department of Plant Pathology, The Ohio State University, Ohio Agricultural Research and Development Center, Wooster, OH 44691, USA
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21
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Adermann K, John H, Ständker L, Forssmann WG. Exploiting natural peptide diversity: novel research tools and drug leads. Curr Opin Biotechnol 2005; 15:599-606. [PMID: 15560988 DOI: 10.1016/j.copbio.2004.10.007] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
During the course of evolution, nature has developed a vast number of peptides in all living and past species that display an exceeding diversity of structure and biological effects, such as hormonal and enzyme-controlling activity, communication between cells, and participation in host defence. Sensitive mass spectrometric technologies have been introduced and facilitate access to new natural peptides, even in trace amounts, and allow the quantitative determination of the peptide status of cells, organs and whole organisms (peptidomics). Among the large number of new biologically active peptides identified from an increasing variety of natural sources, regulators of ion channels, chemoattractants, protease inhibitors, metabolism-related hormones, cytotoxins, and antimicrobials have been found. These novel peptides serve as research tools and have potential as diagnostic biomarkers and for the development of peptide and peptidometic drugs.
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Affiliation(s)
- Knut Adermann
- IPF Pharmaceuticals GmbH, Feodor-Lynen-Strasse 31, 30625 Hannover, Germany.
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22
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Jayakumar A, Kang Y, Henderson Y, Mitsudo K, Liu X, Briggs K, Wang M, Frederick MJ, El-Naggar AK, Bebök Z, Clayman GL. Consequences of C-terminal domains and N-terminal signal peptide deletions on LEKTI secretion, stability, and subcellular distribution. Arch Biochem Biophys 2005; 435:89-102. [PMID: 15680911 DOI: 10.1016/j.abb.2004.12.012] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2004] [Revised: 12/08/2004] [Indexed: 10/26/2022]
Abstract
The secretory lympho-epithelial Kazal-type-inhibitor (LEKTI) is synthesized as a pro-LEKTI protein containing an N-terminal signal peptide and 15 potentially inhibitory domains. This inhibitor is of special interest because of its pathophysiological importance for the severe congenital disease Netherton syndrome. We showed that LEKTI is a potent inhibitor of a family of serine proteinases involved in extracellular matrix remodeling and its expression is downregulated in head and neck squamous cell carcinomas. To assess the role of C-terminal domains and N-terminal signal peptide in LEKTI secretion, we constructed deletion mutants of LEKTI, expressed them in HEK 293T cells, and analyzed their secretion behavior, stability, subcellular distribution, and proteinase inhibitory function. Pro-LEKTI is processed and secreted into the medium. On the basis of partial N-terminal sequencing and immunoblotting, the cleavage products are ordered from amino- to carboxy-terminal as follows: 37, 40, and 60kDa. Inhibitors of furin lead to enhanced secretion of unprocessed LEKTI, suggesting that processing was not required for secretion. Deletion of the N-terminal signal peptide of pro-LEKTI caused altered distribution of LEKTI from endoplasmic reticulum (ER) to cytoplasm and markedly reduced its stability, consistent with its failure to become secreted into the medium. Interestingly, when we deleted the C-terminal domains, stable partial LEKTI (LD-1-6) accumulated and still retained its association with ER but was not secreted. Recombinant LD-1-6 specifically inhibited the trypsin activity. We conclude that N-terminal signal peptide is required for LEKTI import into ER and elements present in C-terminal domains may have a role in regulating LEKTI secretion.
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Affiliation(s)
- Arumugam Jayakumar
- Department of Head and Neck Surgery, The University of Texas M. D. Anderson Cancer Center, Houston, TX 77030-4009, USA
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23
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Galliano MF, Roccasecca RM, Descargues P, Micheloni A, Levy E, Zambruno G, D'Alessio M, Hovnanian A. Characterization and expression analysis of the Spink5 gene, the mouse ortholog of the defective gene in Netherton syndrome. Genomics 2005; 85:483-92. [PMID: 15780751 DOI: 10.1016/j.ygeno.2005.01.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2004] [Accepted: 01/03/2005] [Indexed: 11/19/2022]
Abstract
The human SPINK5 gene, encoding the putative 15-domain serine protease inhibitor LEKTI, was identified as the defective gene in the severe autosomal recessive ichthyosiform skin disorder known as Netherton syndrome and as a candidate susceptibility gene for atopic disease. Here we report mapping of the murine Spink5 gene to chromosome 18 and its characterization. We show that, unlike in humans, transcription of the mouse Spink5 gene generates two mRNAs that differ in the 3' untranslated region. The encoded protein, which is detected in differentiated primary cultured keratinocytes and mouse skin as an approximately 130-kDa glycosylated precursor, displays approximately 60% identity with its human counterpart but lacks the human LEKTI domain 6. As in the human, mouse Lekti represents a marker of epithelial differentiation, strongly expressed in the granular layer of the epidermis, in suprabasal layers of stratified epithelia, and in thymic Hassall's bodies. Our data indicate that mouse Spink5/Lekti, like its human counterpart, is involved in the control of epithelial tissue homeostasis, but also highlight specific features of the murine gene and protein.
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Tidow H, Lauber T, Vitzithum K, Sommerhoff CP, Rösch P, Marx UC. The Solution Structure of a Chimeric LEKTI Domain Reveals a Chameleon Sequence. Biochemistry 2004; 43:11238-47. [PMID: 15366933 DOI: 10.1021/bi0492399] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The conversion of an alpha-helical to a beta-strand conformation and the presence of chameleon sequences are fascinating from the perspective that such structural features are implicated in the induction of amyloid-related fatal diseases. In this study, we have determined the solution structure of a chimeric domain (Dom1PI) from the multidomain Kazal-type serine proteinase inhibitor LEKTI using multidimensional NMR spectroscopy. This chimeric protein was constructed to investigate the reasons for differences in the folds of the homologous LEKTI domains 1 and 6 [Lauber, T., et al. (2003) J. Mol. Biol. 328, 205-219]. In Dom1PI, two adjacent phenylalanine residues (F28 and F29) of domain 1 were substituted with proline and isoleucine, respectively, as found in the corresponding P4' and P5' positions of domain 6. The three-dimensional structure of Dom1PI is significantly different from the structure of domain 1 and closely resembles the structure of domain 6, despite the sequence being identical to that of domain 1 except for the two substituted phenylalanine residues and being only 31% identical to the sequence of domain 6. The mutation converted a short 3(10)-helix into an extended loop conformation and parts of the long COOH-terminal alpha-helix of domain 1 into a beta-hairpin structure. The latter conformational change occurs in a sequence stretch distinct from the region containing the substituted residues. Therefore, this switch from an alpha-helical structure to a beta-hairpin structure indicates a chameleon sequence of seven residues. We conclude that the secondary structure of Dom1PI is determined not only by the local protein sequence but also by nonlocal interactions.
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Affiliation(s)
- Henning Tidow
- Lehrstuhl für Biopolymere, Universität Bayreuth, Universitätsstrasse 30, 95447 Bayreuth, Germany
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25
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Jayakumar A, Kang Y, Mitsudo K, Henderson Y, Frederick MJ, Wang M, El-Naggar AK, Marx UC, Briggs K, Clayman GL. Expression of LEKTI domains 6-9' in the baculovirus expression system: recombinant LEKTI domains 6-9' inhibit trypsin and subtilisin A. Protein Expr Purif 2004; 35:93-101. [PMID: 15039071 DOI: 10.1016/j.pep.2003.12.004] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2003] [Revised: 12/08/2003] [Indexed: 11/27/2022]
Abstract
The precursor lympho-epithelial Kazal-type-related inhibitor (LEKTI), containing two Kazal-type and 13 nonKazal-type domains, is an efficient inhibitor of multiple serine proteinases, among them plasmin, subtilisin A, cathepsin G, elastase, and trypsin. To gain insight into the structure and function of some of these domains, a portion of the cDNA coding for LEKTI domains 6-9' was cloned and expressed in Sf9 cells using the baculovirus expression vector system (BEVS). Through a single purification step using a Co2+ column, 3-4 mg of purified recombinant LEKTI-domains 6-9' (rLEKTI6-9') with the predicted molecular mass of 34.6 kDa was obtained from the cell pellet of a 1-L culture. Unlike full-length LEKTI, rLEKTI6-9' inhibited trypsin and subtilisin A but not plasmin, cathepsin G, or elastase. The inhibition of trypsin and subtilisin A by rLEKTI6-9' occurred through a noncompetitive mechanism, with inhibitory constants (Ki) of 356 +/- 12 and 193 +/- 10 nM, respectively. On the basis of the Ki values, rLEKTI6-9' was determined to be a more potent trypsin inhibitor and a less potent subtilisin A inhibitor than the full-length LEKTI. In contrast to LEKTI domains 6-9', recombinant LEKTI domain 6 does not inhibit subtilisin A but competitively inhibited trypsin with a Ki of 200 +/- 10 nM. Taking LEKTI6-9' as an example, the BEVS should facilitate the structure-function analysis of naturally occurring processed LEKTI forms that have physiological relevance.
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Affiliation(s)
- Arumugam Jayakumar
- Department of Head and Neck Surgery, University of Texas, M.D. Anderson Cancer Center, 1515 Holcombe Blvd., Houston, TX 77030-4095, USA.
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26
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Newlove T, Konieczka JH, Cordes MHJ. Secondary Structure Switching in Cro Protein Evolution. Structure 2004; 12:569-81. [PMID: 15062080 DOI: 10.1016/j.str.2004.02.024] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2003] [Revised: 01/05/2004] [Accepted: 01/05/2004] [Indexed: 11/28/2022]
Abstract
We report the solution structure of the Cro protein from bacteriophage P22. Comparisons of its sequence and structure to those of lambda Cro strongly suggest an alpha-to-beta secondary structure switching event during Cro evolution. The folds of P22 Cro and lambda Cro share a three alpha helix fragment comprising the N-terminal half of the domain. However, P22 Cro's C terminus folds as two helices, while lambda Cro's folds as a beta hairpin. The all-alpha fold found for P22 Cro appears to be ancestral, since it also occurs in cI proteins, which are anciently duplicated paralogues of Cro. PSI-BLAST and transitive homology analyses strongly suggest that the sequences of P22 Cro and lambda Cro are globally homologous despite encoding different folds. The alpha+beta fold of lambda Cro therefore likely evolved from its all-alpha ancestor by homologous secondary structure switching, rather than by nonhomologous replacement of both sequence and structure.
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Affiliation(s)
- Tracey Newlove
- Department of Biochemistry and Molecular Biophysics, University of Arizona, Tucson, AZ 85701 USA
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