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Damberg P, Jarvet J, Gräslund A. Micellar systems as solvents in peptide and protein structure determination. Methods Enzymol 2001; 339:271-85. [PMID: 11462816 DOI: 10.1016/s0076-6879(01)39318-7] [Citation(s) in RCA: 76] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Affiliation(s)
- P Damberg
- Department of Biophysics, Stockholm University, Stockholm S-106 91, Sweden
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Kuttner-Kondo LA, Mitchell L, Hourcade DE, Medof ME. Characterization of the active sites in decay-accelerating factor. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2001; 167:2164-71. [PMID: 11490001 DOI: 10.4049/jimmunol.167.4.2164] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Decay-accelerating factor (DAF) is a complement regulator that dissociates autologous C3 convertases, which assemble on self cell surfaces. Its activity resides in the last three of its four complement control protein repeats (CCP2-4). Previous modeling on the nuclear magnetic resonance structure of CCP15-16 in the serum C3 convertase regulator factor H proposed a positively charged surface area on CCP2 extending into CCP3, and hydrophobic moieties between CCPs 2 and 3 as being primary convertase-interactive sites. To map the residues providing for the activity of DAF, we analyzed the functions of 31 primarily alanine substitution mutants based in part on this model. Replacing R69, R96, R100, and K127 in the positively charged CCP2-3 groove or hydrophobic F148 and L171 in CCP3 markedly impaired the function of DAF in both activation pathways. Significantly, mutations of K126 and F169 and of R206 and R212 in downstream CCP4 selectively reduced alternative pathway activity without affecting classical pathway activity. Rhesus macaque DAF has all the above human critical residues except for F169, which is an L, and its CCPs exhibited full activity against the human classical pathway C3 convertase. The recombinants whose function was preferentially impaired against the alternative pathway C3bBb compared with the classical pathway C4b2a were tested in classical pathway C5 convertase (C4b2a3b) assays. The effects on C4b2a and C4b2a3b were comparable, indicating that DAF functions similarly on the two enzymes. When CCP2-3 of DAF were oriented according to the crystal structure of CCP1-2 of membrane cofactor protein, the essential residues formed a contiguous region, suggesting a similar spatial relationship.
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Affiliation(s)
- L A Kuttner-Kondo
- Department of Pathology, Case Western Reserve University, Cleveland, OH 44106, USA
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Henderson CE, Bromek K, Mullin NP, Smith BO, Uhrín D, Barlow PN. Solution structure and dynamics of the central CCP module pair of a poxvirus complement control protein. J Mol Biol 2001; 307:323-39. [PMID: 11243823 DOI: 10.1006/jmbi.2000.4477] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The complement control protein (CCP) module (also known as SCR, CCP or sushi domain) is prevalent amongst proteins that regulate complement activation. Functional and mutagenesis studies have shown that in most cases two or more neighbouring CCP modules form specific binding sites for other molecules. Hence the orientation in space of a CCP module with respect to its neighbours and the flexibility of the intermodular junction are likely to be critical for function. Vaccinia virus complement control protein (VCP) is a complement regulatory protein composed of four tandemly arranged CCP modules. The solution structure of the carboxy-terminal half of this protein (CCP modules 3 and 4) has been solved previously. The structure of the central portion (modules 2 and 3, VCP approximately 2,3) has now also been solved using NMR spectroscopy at 37 degrees C. In addition, the backbone dynamics of VCP approximately 2,3 have been characterised by analysis of its (15)N relaxation parameters. Module 2 has a typical CCP module structure while module 3 in the context of VCP approximately 2,3 has some modest but significant differences in structure and dynamics to module 3 within the 3,4 pair. Modules 2 and 3 do not share an extensive interface, unlike modules 3 and 4. Only two possible NOEs were identified between the bodies of the modules, but a total of 40 NOEs between the short intermodular linker of VCP approximately 2,3 and the bodies of the two modules determines a preferred, elongated, orientation of the two modules in the calculated structures. The anisotropy of rotational diffusion has been characterised from (15)N relaxation data, and this indicates that the time-averaged structure is more compact than suggested by (1)H-(1)H NOEs. The data are consistent with the presence of many intermodular orientations, some of which are kinked, undergoing interconversion on a 10(-8)-10(-6) second time-scale. A reconstructed representation of modules 2-4 allows visualisation of the spatial arrangement of the 11 substitutions that occur in the more potent complement inhibitor from Variola (small pox) virus.
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Affiliation(s)
- C E Henderson
- The Edinburgh Centre for Protein Technology, the University of Edinburgh, the Joseph Black Chemistry Building, the King's Buildings, West Mains Road, Edinburgh EH9 3JJ, UK
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Palczewska M, Groves P, Kuznicki J. Use of Pichia pastoris for the expression, purification, and characterization of rat calretinin "EF-hand" domains. Protein Expr Purif 1999; 17:465-76. [PMID: 10600467 DOI: 10.1006/prep.1999.1154] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Calretinin (CR) is a calcium-binding, neuronal protein of undefined function. Related proteins either buffer intracellular calcium concentrations or are involved in calcium-signaling pathways. We transformed three CR gene fragment sequences, corresponding to its three complementary domains (I-II, III-IV, and V-VI), into Pichia pastoris. High yields of extracellular expression, of more than 200 mg/liter, were achieved. Simple purification protocols provide high yields of homogenous proteins: dialysis and DEAE-cellulose chromatography for domains I-II and III-IV or ammonium sulfate precipitation and octyl-Sepharose chromatography for domain V-VI. To our knowledge, this is the first report of the expression of an EF-hand protein using P. pastoris. Direct comparison of the purified yields of domain I-II indicates a approximately 20-fold improvement over Escherichia coli. N-terminal amino acid sequencing confirmed our gene products and two anti-calretinin antibodies recognized the appropriate domains. All three CR domains bind (45)Ca and the domain containing EF-hands V and VI seems to have a lower calcium capacity than the other domains. Circular dichroism indicates a high helix content for each of the domains. Calcium-induced structural changes in the first two domains, followed by tryptophan fluorescence, correspond with previous studies, while tyrosine emission fluorescence indicates calcium-induced structural changes also occur in domain V-VI. The methods and expression levels achieved are suitable for future NMR labeling of the proteins, with (15)N and (13)C, and structure-function studies that will help to further understand CR function.
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Affiliation(s)
- M Palczewska
- Department of Molecular and Cellular Neurobiology, Nencki Institute of Experimental Biology, 3 Pasteur Street, Warsaw, 02-093, Poland
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Symons A, Willis AC, Barclay AN. Domain organization of the extracellular region of CD45. PROTEIN ENGINEERING 1999; 12:885-92. [PMID: 10556250 DOI: 10.1093/protein/12.10.885] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
CD45 is a large, heavily glycosylated, transmembrane protein phosphotyrosine phosphatase found on all nucleated cells of haematopoietic origin. In lymphocytes, the cytoplasmic phosphatase is necessary for efficient signalling through the antigen receptor but in contrast little is known about the interactions of the extracellular region of the molecule. This consists of a mucin-like region, a novel cysteine-containing region and a region containing three putative fibronectin type III domains. To confirm this organization and to identify parts potentially important for function, we have expressed fragments of the extracellular domain of rat CD45 as recombinant soluble proteins. Proteins corresponding to two, three and four domains of CD45 were expressed in secreted forms. Single domains and constructs for proteins with truncations of the predicted domains were not expressed. This is consistent with the proposed structural organization. Determination of the positions of the disulphide bonds in the N-terminal cysteine-containing region and the first fibronectin type III domain identified novel disulphide bonds within the fibronectin type III domain and an unusual inter-domain disulphide linkage. Circular dichroism spectroscopy indicated that this region of rat CD45 has mainly beta-strand secondary structure and no alpha-helical content. These studies support the proposed domain organization of CD45.
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Affiliation(s)
- A Symons
- MRC Cellular Immunology Unit, Sir William Dunn School of Pathology, University of Oxford, Oxford, OX1 3RE
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Navarre WW, Schneewind O. Surface proteins of gram-positive bacteria and mechanisms of their targeting to the cell wall envelope. Microbiol Mol Biol Rev 1999; 63:174-229. [PMID: 10066836 PMCID: PMC98962 DOI: 10.1128/mmbr.63.1.174-229.1999] [Citation(s) in RCA: 925] [Impact Index Per Article: 37.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The cell wall envelope of gram-positive bacteria is a macromolecular, exoskeletal organelle that is assembled and turned over at designated sites. The cell wall also functions as a surface organelle that allows gram-positive pathogens to interact with their environment, in particular the tissues of the infected host. All of these functions require that surface proteins and enzymes be properly targeted to the cell wall envelope. Two basic mechanisms, cell wall sorting and targeting, have been identified. Cell well sorting is the covalent attachment of surface proteins to the peptidoglycan via a C-terminal sorting signal that contains a consensus LPXTG sequence. More than 100 proteins that possess cell wall-sorting signals, including the M proteins of Streptococcus pyogenes, protein A of Staphylococcus aureus, and several internalins of Listeria monocytogenes, have been identified. Cell wall targeting involves the noncovalent attachment of proteins to the cell surface via specialized binding domains. Several of these wall-binding domains appear to interact with secondary wall polymers that are associated with the peptidoglycan, for example teichoic acids and polysaccharides. Proteins that are targeted to the cell surface include muralytic enzymes such as autolysins, lysostaphin, and phage lytic enzymes. Other examples for targeted proteins are the surface S-layer proteins of bacilli and clostridia, as well as virulence factors required for the pathogenesis of L. monocytogenes (internalin B) and Streptococcus pneumoniae (PspA) infections. In this review we describe the mechanisms for both sorting and targeting of proteins to the envelope of gram-positive bacteria and review the functions of known surface proteins.
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Affiliation(s)
- W W Navarre
- Department of Microbiology & Immunology, UCLA School of Medicine, Los Angeles, California 90095, USA
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Hawrot E, Xiao Y, Shi QL, Norman D, Kirkitadze M, Barlow PN. Demonstration of a tandem pair of complement protein modules in GABA(B) receptor 1a. FEBS Lett 1998; 432:103-8. [PMID: 9720905 DOI: 10.1016/s0014-5793(98)00794-7] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
We have subcloned and expressed the N-terminal portion of the recently sequenced metabotropic GABA receptor, GABA(B)R1a. This region of the receptor contains a complement protein-like amino acid sequence. The purified 140-residue recombinant protein fragment was soluble and stable. Mass spectrometry indicated formation of four disulfide bonds, as expected if two complement protein modules (CPs, also known as SCRs, Sushi domains) are formed. The circular dichroism spectrum was unusual and characteristic of CPs. Differential scanning calorimetry demonstrated a melting point (64 degrees C), and total enthalpy commensurate with two fully folded domains. We thus conclude that the 1a subtype of the GABA(B) receptor, but not the 1b subtype, contains a pair of CPs and we present a three-dimensional model of this region.
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Affiliation(s)
- E Hawrot
- Department of Molecular Pharmacology, Physiology and Biotechnology, Brown University, Providence, RI 02192, USA
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Blackmore TK, Hellwage J, Sadlon TA, Higgs N, Zipfel PF, Ward HM, Gordon DL. Identification of the Second Heparin-Binding Domain in Human Complement Factor H. THE JOURNAL OF IMMUNOLOGY 1998. [DOI: 10.4049/jimmunol.160.7.3342] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Abstract
Complement factor H (fH) regulates activation of the alternative pathway of C, reducing the amount of C3b deposited on sialic acid-rich surfaces. Heparin binding has been used as a model for examining the sialic acid-binding characteristics of fH. We have previously shown that of the 20 short consensus repeat (SCR) modules of fH, SCR 7 contains an important heparin binding site, but other SCRs also play a role in heparin binding. To localize the other sites, we prepared recombinant truncated and SCR deletion mutants of fH and tested them by heparin-agarose affinity chromatography. The 5 C-terminal SCRs were found to contain a heparin binding site as an SCR 7 deletion mutant of the N terminal 15 SCRs did not bind heparin, but a construct consisting of SCRs 16–20 was shown to bind heparin. Double deletion of SCRs 7 and 20 from fH abrogated binding to heparin, indicating that SCR 20 contains a heparin binding site. This finding was confirmed with the observation that attachment of SCR 20 to a group of nonbinding SCRs produced a heparin-binding protein. A protein consisting of SCRs 19 and 20 did not bind heparin, whereas SCRs 18–20 did, indicating that, although SCR 20 contains a heparin binding site, at least two nonspecific adjacent SCRs are required. fH-related protein-3 (FHR-3) possesses an SCR homologous to SCR 7 of fH and bound heparin, whereas FHR-4, which lacks such an SCR, did not. Thus, fH contains two separate heparin binding sites, which are located in SCRs 7 and 20.
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Affiliation(s)
- Timothy K. Blackmore
- *Department of Microbiology and Infectious Diseases, Flinders Medical Centre, Bedford Park, South Australia, Australia; and
| | - Jens Hellwage
- †Department of Molecular Biology, Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
| | - Tania A. Sadlon
- *Department of Microbiology and Infectious Diseases, Flinders Medical Centre, Bedford Park, South Australia, Australia; and
| | - Naomi Higgs
- *Department of Microbiology and Infectious Diseases, Flinders Medical Centre, Bedford Park, South Australia, Australia; and
| | - Peter F. Zipfel
- †Department of Molecular Biology, Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
| | - Helena M. Ward
- *Department of Microbiology and Infectious Diseases, Flinders Medical Centre, Bedford Park, South Australia, Australia; and
| | - David L. Gordon
- *Department of Microbiology and Infectious Diseases, Flinders Medical Centre, Bedford Park, South Australia, Australia; and
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