Interpretation of biological activity data of bacterial endotoxins by simple molecular models of mechanism of action

European Journal of Biochemistry

Volumn 267, Issue 3, 2000, Pages 837-852

  Frecer, Vladimir ^a   Ho, Bow ^b   Ding, Jeak L ^a  

^a NATIONAL UNIVERSITY OF SINGAPORE   (Singapore)

^b NATIONAL UNIVERSITY OF SINGAPORE   (Singapore)

Author keywords

Correlation with Limulus assay; Endotoxin; Lipid A; Molecular mechanism of action; Molecular modelling

Indexed keywords

AMINO ACID; AMMONIA; ENDOTOXIN; LIPID A; LIPOPOLYSACCHARIDE; PHOSPHATE; PROTEIN; RECEPTOR;

ARTICLE; BINDING AFFINITY; BINDING SITE; DRUG ACTIVITY; MOLECULAR MODEL; NONHUMAN; PRIORITY JOURNAL;

BACTERIA (MICROORGANISMS); ESCHERICHIA COLI; LIMULUS;

EID: 84961979617     PISSN: 00142956     EISSN: None     Source Type: Journal    
DOI: 10.1046/j.1432-1327.2000.01069.x     Document Type: Article

References (100)

1. 1. Takada, H., Kotani, S. & (1989) Structural requirements of lipid A for endotoxic and other biological activities. CRC Crit. Rev. Microbiol. 16, 477-523.
2. 2. Rietschel, E.Th., Brade, H., Holst, O., Brade, L., Müller-Loennies, S., Mamat, U., Zähringer, U., Beckmann, F., Seydel, U., Brandenburg, K., Ulmer, A.J., Mattern, T., Heine, H., Schletter, S., Hauschildt, S., Loppnow, H., Schönbeck, U., Flad, H.-D., Schade, U.F., Di Padova, F., Kusumoto, S. & Schumann, R.R. (1995) Bacterial endotoxin: chemical constitution, biological recognition, host response, and immunological detoxification. Curr. Top. Microbiol. Immunol. 216, 39-81.
3. 3. Raetz, Ch.R.H. (1993) Bacterial endotoxins: extraordinary lipids that activate eucaryotic signal transduction. J. Bacterial. 175, 5745-5753.
4. 4. Cross, A.S. & Opal, S.M. (1994) Therapeutic intervention in sepsis with antibody to endotoxins: is there future? J. Endotoxin Res. 1, 57-69.
5. 5. Galanos, C., Lüderitz, O., Rietschel, E.Th., Westphal, O., Brade, H., Brade, L., Freudenberg, M., Schade, U., Imoto, M., Yoshimura, H., Kusumoto, S. & Shiba, T. (1985) Synthetic and natural Escherichia coli lipid A expresses identical endotoxic activity. Eur. J. Biochem. 148, 1-5.
6. 6. Kotani, S., Takada, H., Tsujimoto, M., Ogawa, T., Takahashi, I., Ikeda, T., Otsuka, K., Shimauchi, H., Kasai, N., Mashimo, J., Nagao, S., Tanaka, A., Tanaka, S., Harada, K., Nagaki, K., Kitamura, H., Shiba, T., Kusumoto, S., Imoto, M. & Yoshimura, H. (1985) Synthetic lipid A with endotoxic and related biological activities comparable to those of a natural lipid A form from an Escherichia coli RE-mutant. Infect. Immun. 49, 225-237.
7. 7. Schumann, R.R., Leong, S.R., Flags, G.W., Gray, P.W., Wright, S.D., Mathison, J.C., Tobias, P.S. & Ulevich, R.J. (1990) Structure and function of lipopolysaccharide binding protein. Science 249, 1429-1431.
8. 8. Wright, S.D., Ramos, R.A., Tobias, P.S., Ulevich, R.J. & Mathinson, J.C. (1990) CD14, a receptor for complexes of lipopolysaccharide (LPS) and LPS binding protein. Science 249, 1431-1433.
9. 9. Wright, S.D., Ramos, R.A., Patel, M. & Miller, D.S. (1992) Septin: a factor in plasma that opsonizes lipopolysaccharide-bearing particles for recognition by CD14 on phagocytes. J. Exp. Med. 176, 719-727.
10. 10. Simmons, D.L., Tan, S., Tenen, D.G., Nicholson-Weller, A. & Seed, B. (1989) Monocyte antigen CD14 is a phospholipid anchored membrane protein. Blood 73, 284-289.
11. 11. Yang, R.B.Mark, M.R., Gray, A., Huang, A., Xie, M.H., Zhang, H., Goddard, A., Wood. W.I., Gurney, A.L. & Godowski P.J. (1998) Toll-like receptor-2 mediates lipopolysaccharide-induced cellular signalling. Nature, 17, 284-288.
12. 12. Rock, F.L., Hardiman, G., Timas, J.C., Kastelein, R.A. & Bazan J.F. (1998) A family of human receptors structurally related to Drosophila toll. Proc. Natl Acad. Sci. USA 95, 588-593.
13. 13. Ulevich, R.J. & Tobias, P.S. (1999) Recognition of Gram-negative bacteria & endotoxin by the innate immune system. Curr. Opinion Immunol. 11, 19-22.
14. 14. Dinarello, C.A. (1991) Interleukin-1 and interleukin-1 antagonism. Blood 77, 1627-1652.
15. 15. Beutler, B. & Cerami, A. (1988) Tumour necrosis, cachexia, shock, and inflammation: a common mediator. Annu. Rev. Biochem. 57, 505-518.
16. 16. Couturier, C., Haeffner-Cavaillon, N., Caroff, M. & Kazatchkine, M. (1991) Binding sites for endotoxins (lipopolysaccharides) on human monocytes. J. Immunol. 147, 1899-1904.
17. 17. Tobias, P.S., Soldau, K. & Ulevitch, R.J. (1989) Identification of a lipid A binding site in the acute phase reactant lipopolysaccharide binding protein. J. Biol. Chem. 264, 10867-10871.
18. 18. Jacobs, D.M. (1984) Structural features of binding of lipopolysaccharides to murine lymphocytes. Rev. Infect. Dis. 6, 501-505.
19. 19. Larsen, N.E., Enelow, R.I., Simons, E.R. & Sullivan, R. (1985) Effect of bacterial endotoxin on the transmembrane electrical potential and plasma membrane fluidity of human monocytes. Biochim. Biophys. Acta 815, 1-8.
20. 20. Portoles, M.T., Pagani, R., Diaz-Laviada. I. & Munncio, A.M. (1987) Effect of Escherichia coli lipopolysaccharide on the microviscosity of liver plasma membranes and hepatocyte suspensions and monolayers. Cell Biochem. Funct. 5, 55-61.
21. 21. Brandenburg, K., Mayer, H., Koch, M.J., Weckesser, J., Rietschel, E.Th. & Seydel, U. (1993) Influence of the supramolecular structure of free lipid A on its biological activity. Eur. J. Biochem. 218, 555-563.
22. 22. Seydel, U., Labischinski, H., Kastowsky, M. & Brandenburg, K. (1993) Phase behavior, supramolecular structure, and molecular conformation of lipopolysaccharide. Immunobiol. 187, 191-211.
23. 23. Morison, D.C. (1989) The case for specific lipopolysaccharide receptors expressed on mammalian cells. Microb. Pathog. 7, 389-398.
24. 24. Takayama, K., Mitchel, D.H., Din, Z.Z., Mukerjee, P., Li, C. & Coleman, D.L. (1994) Monomeric Re lipopolysaccharide from Escherichia coli is more active than aggregated form in the Limulus amebocyte lysate assay and in inducing Egr-1 mRNA in murine macrophages. J. Biol. Chem. 269, 2241-2244.
25. 25. Takayama, K., Din, Z.Z., Mukerjee, P., Cooke, H. & Kirkland, T.N. (1990) Physicochemical properties of the lipopolysaccharide unit that activates B lymphocytes. J. Biol. Chem. 265, 14023-14029.
26. 26. Risco, C. & Pinto da Silva, P. (1995) Cellular functions during activation and damage by pathogens: immunogold studies of the interaction of bacterial endotoxins with target cells. Microsc. Res. Technical 31, 141-158.
27. 27. Din, Z.Z., Mukerjee, P., Kastowski, M., Takayama, K. & (1993) Effect of pH on solubility and ionic state of lipopolysaccharide obtained from deep rough mutant of Escherichia coli. Biochemistry 32, 4579-4586.
28. 28. Mattsby-Baltzer, I., Lindgren, K. & Lindholm, B., Edebo, L. (1991) Endotoxin shedding by enterobacteria: free and cell-bound endotoxin differ in Limulus activity. Infect. Immun. 59, 689-695.
29. 29. Iwanaga, S., Morita, T., Miyata, T. & Nakamura, T. (1985) Hemolymph coagulation system in Limulus. In Microbiology (Schlessinger, L., eds), pp. 29-32. American Society for Microbiology, Washington, DC.
30. 30. Takada, H., Kotani, S., Tanaka, S., Ogawa, T., Takahashi, I., Tsujimoto, M., Kumuro, T., Shiba, T., Kusumoto, S., Kusunose, N., Hasegawa, A. & Kiso, M. (1988) Structural requirements of lipid A species in activation of clotting enzymes from the horseshoe crab, and the human complement cascade. Eur. J. Biochem. 175, 573-580.
31. 31. Lüderitz, O., Galanos, C., Lehmann, V., Meyer, H., Rietschel, E.Th. & Weckesser, J. (1978) Chemical structure and biological activities of lipid As from various bacterial families. Naturwissenschaften 65, 578-585.
32. 32. Imoto, M., Kusumoto, S., Shiba, T., Naoki, H., Rietschel, E.Th., Galanos, C. & Lüderitz, O. (1985) Chemical structure of Escherichia coli lipid A. Tetrahedron Lett. 26, 907-908.
33. 33. Momany, F., Pitha, R., Klimkowsky, V.J. & Venkatachalam, C.M. (1989) Drug design using a protein pseudoreceptor. In Expert Systems and Applications in Chemistry (Hohne, B.A. & Pierce, T.H., eds), pp. 82-91. American Chemical Society Symposia Series 408, Washington, DC.
34. 34. Snyder, J.P., Rao, S.N., Koehler, K.F. & Pellicciari, R. (1992) Drug modelling at cell membrane receptors: the concept of pseudoreceptors. In Trends in Receptor Research (Angeli, P., Gulini, U. & Quaglia, W., eds), pp. 367-403. Elsevier Science Publishers, Amsterdam, the Netherlands.
35. 35. Hahn, M. (1995) Receptor surface models. 1. Definition and construction. J. Med. Chem. 38, 2080-2090.
36. 36. Vedani, A., Zbinden, P., Snyder, J.P. & Greenidge, P.A. (1995) Pseudoreceptor modeling: the construction of three-dimensional receptor surrogates. J. Am. Chem. Soc. 117, 4987-4994.
37. 37. Kastowsky, M., Sabisch, A., Gutberlet, T., Bradaczek, H. (1991) Molecular modelling of bacterial deep rough mutant lipopolysaccharide of Escherichia coli. Eur. J. Biochem. 197, 707-716.
38. 38. Kastowsky, M., Gutberlet, T. & Bradaczek, H. (1992) Molecular modelling of three-dimensional structure and conformational flexibility of bacterial lipopolysaccharide. J. Bacterial. 174, 4798-4806.
39. 39. Wang, Y. & Hollingsworth, R.I. (1996) An NMR and molecular mechanics study of the molecular basis for the supramolecular structure of lipopolysaccharides. Biochemistry 35, 5647-5654.
40. 40. Jung, S., Min, D. & Hollingsworth, R.I. (1996) A Metropolis Monte Carlo method for analyzing the energetics and dynamics of lipopolysaccharide supramolecular structure and organization. J. Comput. Chem. 17, 238-249.
41. 2+. Biophys. J. 72, 1031-1046.
42. 42. Karikae, T., Schade, F.U., Zähringer, U., Karikae, F., Brade, H., Kusumoto, S., Kusama, T. & Rietschel, E.Th. (1994) The significance of the hydrophilic backbone and the hydrophobic fatty acid regions of lipid A for macrophage binding and cytokine induction. FEMS Immunol. Med. Microbiol. 8, 13-26.
43. 43. Schromm, A.B., Brandenburg, K., Loppnow, H., Zähringer, U., Rietschel, E.Th., Carroll, S.F., Koch, M.H.J., Kusumoto, S. & Seydel, U. (1998) The charge of endotoxin molecules influences their conformation and IL-6-inducing capacity. J. Immunol. 161, 5464-5471.
44. 44. Hoess, A., Watson, S., Siber, G.R. & Liddington, R. (1993) Crystal structure of an endotoxin-neutralizing protein from the horseshoe crab, Limulus anti-LPS factor, at 1.5 Å resolution. EMBO J. 12, 3351-3356.
45. 45. Rasmussen, B., Wiberg, F.C., Flodgaard, H.J. & Kjøller Larsen, I. (1997) Structure of HBP, a multifunctional protein with a serine protease fold. Nat. Struct. Biol. 4, 265-268.
46. 46. Beamer, L.J., Carroll, S.E & Eisenberg, D. (1997) Crystal Structure of human BPI and two bound phospholipids at 2.4 Angstrom resolution. Science 276, 1861-1864.
47. 47. Koizumi, N., Morozumi, A., Imamura, M., Tanaka, E., Iwahana, H. & Sato, R. (1997) Lipopolysaccharide-binding proteins and their involvement in the bacterial clearance from the hemolymph of the silkworm Bombyx mori. Eur. J. Biochem. 248, 217-224.
48. 48. Marra, M.N., Wide, C.G., Collins, M.S., Snable, J.L., Thornton, M.B. & Scott, R.W. (1992) The role of bactericidal/permeability-increasing protein as a natural inhibitor of bacterial endotoxin. J. Immunol. 148, 532-573.
49. 49. Larrick, J.W., Hirata, M., Balint, R.F., Lee, J., Zhong, J. & Wright, S.C. (1995) Human CAP-18: a novel antimicrobial lipopolysaccharide-binding protein. Infect. Immun. 63, 1291-1297.
50. 50. Vaara, M. & Vaara, T. (1983) Sensitization of Gram-negative bacteria to antibiotics and complement by a nontoxic oligopeptide. Nature 303, 526-528.
51. 51. Larrick, J.W., Hirata, M., Shimomoura, Y., Yoshida, M., Zheng, H., & Wright, S.C. (1993) Antimicrobial activity of rabbit CAP-18-derived peptides. Antimcrob. Agents Chemother. 37, 2534-2539.
52. 52. Rustici, A., Velucchi, M., Faggioni, R., Sironi, M., Ghezzi, P., Quataet, S., Green, B. & Porro, M. (1993) Molecular mapping and detoxification of the lipid A binding site by synthetic peptides. Science 259, 361-365.
53. 53. Kloczewiak, M., Black, K.M., Loiselle, P., Cavaillon, J.-M. & Wainwright, N.J. (1994) Synthetic peptides that mimic the binding site of horseshoe crab antilipopolysaccharide factor. Infect. Dis. 170, 1490-1497.
54. 54. Taylor, A.H., Haevner, G., Nedelman, M., Sherris, D., Brunt, E., Knight, D. & Ghrayeb, J. (1995) Lipopolysaccharide (LPS) neutralizing peptides reveal a lipid A binding site of LPS binding protein. J. Biol. Chem. 270, 17934-17938.
55. 55. Juan, T.S.-C., Hailman, E., Kelley, M.J., Busse, L.A., Davy, E., Empig, C.J., Narhi, L.O., Wright, S.D. & Lichenstein, H.S. (1995) Identification of a lipopolysaccharide binding domain in CD14 between amino acids 57 and 64. J. Biol. Chem. 270, 5219-5224.
56. 56. Elass-Rochard, E., Roseanu, A., Legrand, D., Trif, M., Salmon, V., Motas, C., Montreuil, J. & Spik, G. (1995) Lactoferrin - lipopolysaccharide interaction: involvement of the 28-34 loop region of human lactoferrin in the high affinity binding to Escherichia coli O55B5 lipopolysaccharide. Biochem. J. 312, 839-845.
57. 57. Ried, C., Wahl, C., Miethke, T., Wellhofer, G., Landgraf, C., Schneider-Mergener, J. & Hoess, A. (1996) High affinity endotoxin-binding and neutralizing peptides based on the crystal structure of a recombinant Limulus anti-lipopolysaccharide factor. J. Biol. Chem. 271, 28120-28127.
58. 58. Unkis, M.E., Wasiluk, K.R., Acton, R.D., Klarner, H.G., Dahlberg, P.S., Ilyina, E.E., Haseman, J.R., Gray, B.H., Mayo, K.H. & Dunn, D.L. (1997) Design of a potent novel endotoxin antagonist. Surgery 122, 380-385.
59. 59. de Haas, C.J.C., Van der Tol, M.E., Van Kessel, K.P.M., Verhoef, J. & Van Strijp, J.A.G. (1998) A synthetic lipopolysaccharide-binding peptide based on amino acids 27-39 of serum amyloid P component inhibits lipopolysaccharide-induced responses in human blood. J. Immunol. 161, 3607-3615.
60. 60. Zhang, G.-H., Mann, D.M., Tsai, C.-M. & (1999) Neutralization of endotoxin in vitro and in vivo by human lactoferrin-derived peptide. Infec. Immun. 67, 1353-1358.
61. 61. Scott, M.G., Yan, H. & Hancock, R.E.W. (1999) Biological properties of structurally related α-helical cationic antimicrobial peptides. Infect. Immun. 67, 2005-2009.
62. 62. Gough, M., Hancock, R.E.W. & Kelly, N.M. (1996) Antiendotoxin activity of cationic peptide antimicrobial agents. Infect. Immun. 64, 4922-4927.
63. 63. Pereira, H.A., Erdem, I., Pohl, J. & Spitznagel, J.K. (1993) Synthetic bactericidal peptide based on CAP37: a 37-kDa human neutrophil granule-associated cationic antimicrobial protein chemotactic for monocytes. Proc. Natl Acad. Sci. USA 90, 4733-4737.
64. 64. Skerlavaj, B., Gennaro, R., Bagella, L., Merluzzi, L., Risso, A. & Zanetti, M. (1996) Biological characterization of two novel cathelicidin-derived peptides and identification of structural requirements for their antimicrobial and cell lytic activities. J. Biol. Chem. 271, 28375-28381.
65. 65. Oh, J.E., Hong, S.Y. & Lee, K.-H. (1999) Structure-activity relationships study: short antimicrobial peptides. J. Pept. Res. 53, 41-46.
66. 66. Agerberth, B., Cunne, H., Odeberg, J., Kogner, P., Boman, H.G., & Gudmundsson, G.H. (1995) FALL-39, a putative human peptide antibiotic, is cysteine free and expressed in bone marrow and testis. Proc. Natl Acad. Sci. USA 92, 195-199.
67. 67. Osaki, T., Omotezako, M., Nagayama, R., Hirata, M., Iwanaga, S., Kasahara, J., Hattori, J., Ito, I., Sugiyama, H. & Kawabata, S. (1999) Horseshoe crab hemocyte-derived antimicrobial polypeptides, tachystatins, with sequences similarity to spider neurotoxins. J. Biol. Chem. 274, 26172-26178.
68. 68. David, S.A., Bachtel, B., Annaiah, C., Mathan, V.I. & Balaram, P. (1994) Interaction of cationic amphiphilic drugs with lipid A: Implications for development of endotoxin antagonists. Biochim. Biophys. Acta 1212, 167-175.
69. 69. Stokes, D.C., Shenep, J.L., Fishman, M., Hildner, W.K., Bysani, G.K. & Rufus, K. (1989) Polymyxin B prevents lipopolysaccharide-induced release of tumour necrosis factor-alpha from alveolar macrophages. J. Infect. Dis. 160, 52-57.
70. 70. Insight II®, Discover®, Delphi and Biopolymer User Guide (1995). Biosym/MSI & October, San Diego, CA.
71. 71. Robinson, A.J., Richards, W.G., Thomas, P.J. & Kann, M.M. (1994) Head group and chain dynamics in biological membranes: a molecular dynamics computer simulation. Biophys. J. 67, 2345-2354.
72. 72. Maple, J.R., Hwang, M.-J., Stockfish, T.P., Dinur, U., Waldman, M., Ewing, C.S. & Hagler, A.T. (1994) Derivation of class II force fields. 1. Methodology and quantum force filed for the alkyl functional group and alkane molecules. J. Comput. Chem. 15, 162-182.
73. 73. Maple, J.R., Hwang, M.-J., Stockfish, T.P. & Hagler, A.T. (1994) Derivation of class II force fields. 3. Characterization of a quantum force field for alkanes. Israel J. Chem. 34, 195-231.
74. 74. Asensio, J.M., Martin-Pastor, M. & Jimenez-Barbero, J. (1995) The use of CVFF and CFF91 force fields in conformational analysis of carbohydrate molecules. Comparison with AMBER molecular mechanics and dynamics calculations for methyl alpha-lactoside. Int. J. Biol. Macromol. 17, 137-148.
75. 75. Lee, C.H. & Zimmerman, S.S. (1995) Calculation of the phi-psi conformational contour maps for N-acetyl alanine N′-methylamide and characteristic ratios of poly-L-alanine using various molecular mechanics forcefields. J. Biomol. Stuct. Dyn. 13, 201-218.
76. 76. Allen, M.P. & Tildesley, D.J. (1987) Computer Simulations of Liquids. Oxford University Press, Oxford.
77. 5-deazapterins to dihydrofolate reductase. Protein Eng. 10, 23-30.
78. 78. Brunger, A.T. & Krukowski, A. (1990) Slow-cooling protocols for crystallographic refinement by simulated annealing. Acta Crystallogr. A46, 585-593.
79. 79. Laughton, C.A. (1994) A study of simulated annealing protocols for use with molecular dynamics in protein structure prediction. Protein Eng. 7, 235-241.
80. 80. Ponder, J.W. & Richards, F.M. (1987) Tertiary templates for proteins. Use of packing criteria in the enumeration of allowed sequences for different structural classes. J. Mol. Biol. 193, 775-791.
81. 81. Shoichet, B.K., Leach, A.R. & Kuntz, I.D. (1999) Ligand solvation in molecular docking. Proteins 34, 4-16.
82. 82. Frecer, V., Miertus, S., Tossi, A. & Romeo, D. (1998) Rational design of inhibitors for drug resistant HIV-1 aspartic protease mutants. Drug Des. Disc. 15, 211-231.
83. 83. Lewis, R.A. (1998) Lewis' Dictionary of Toxicology. Lewis Publishers, Boca Raton, FL.
84. 84. Tomasi, J. & Persico, M. (1994) Molecular interactions in solutions: an overview of methods based on continuous distributions of the solvent. Chem. Rev. 94, 2027-2094.
85. 85. Miertus, S., Scrocco, E. & Tomasi, J. (1981) Electrostatic interaction of a solute with a continuum. A direct utilization of ab initio molecular potentials for the prevision of solvent effect. Chem. Phys. 55, 117-129.
86. 86. Frecer, V. & Miertus, S. (1992) Polarizable continuum model of solvation for biopolymers. Int. J. Quant. Chem. 42, 1449-1468.
87. 87. Thole, B.T. (1981) Molecular polarizabilities calculated with a modified dipole interaction. Chem. Phys. 59, 341-350.
88. 88. Miertus, S., Furlan, M., Tossi, A. & Romeo, D. (1996) Design of new inhibitors of HIV-1 aspartic protease. Chem. Phys. 204, 173-180.
89. -. J. Inc. Phenom. Mol. Recogn. 32, 23-46.
90. 90. Winkler, S., Overbeek, R., Woese, C.R., Olsen, G.J. & Pfluger, N. (1990) Structure detection through automated covariance search. Comput. Appl. Biosci. 6, 365-371.
91. 91. Engleman, D.M. & Steitz, T.A. (1981) The spontaneous insertion of proteins into and across membranes: the helical hairpin hypothesis. Cell 23, 411-422.
92. 92. Kyte, J. & Doolittle, R.F. (1982) A simple method for displaying the hydropathic character of a protein. J. Mol. Biol. 157, 105-132.
93. 93. Eisenberg, D., Weiss, R.M. & Terwilliger, T.C. (1982) The helical hydrophobic moment: a measure of the amphiphilicity of a helix. Nature 299, 371-374.
94. 94. Thompson, J.D., Higgins, D.G. & Gibson, T.J. (1994) CLUSTAL W: improving the sensitivity of progresssive multiple sequence alignment through weighting position-sensitive gap penalties and weight matrix choice. Nucleic Acid Res. 22, 4673-4680.
95. 95. Heinikoff, S. & Heinikoff, J.G. (1992) Amino acid substitution matrices from protein blocks. Proc. Nad Acad. Sci. USA 89, 10915-10919.
96. 2 torsional terms. J. Am. Chem. Soc. 99, 8127-8134.
97. 97. Mayo, S.L., Olafson, B.D. & Goddard, W.A. (1990) Dreiding - a generic force-field for molecular simulations. J. Phys. Chem. 94, 8897-8909.
98. 98. Brooks, B.R., Bruccoleri, R.E., Olafson, B.D., States, D.J., Swaminathan, S. & Karplus, M. (1983) CHARM: a program for macromolecular energy, minimization and dynamics calculations. J. Comput. Chem. 4, 187-217.
99. 99. Ding, J.L., Navas, M.A.A. & Ho, B. (1993) Two forms of factor C from the amoebocytes of Carcinoscorpius rotundicauda; purification and characterisation. Biochem. Biophys. Acta 1202, 149-156.
100. 100. Ding, J.L., Navas, M.A.A. & Ho, B. (1995) Molecular cloning and sequence analysis of factor C cDNA from the Singapore horseshoe crab, Carcinoscorpius rotundicauda. Mol. Mar. Biol. Biotechnol. 4, 90-103.