Model and design of peptidic
agonists - Biological and biophysical studies of Endothelin peptides
My main are of research lies
on the structural elucidation of small and macro molecules by NMR and molecular
modelling techniques. I am also interested in three dimensional solution
structure calculations for peptides and small molecules using various modelling
methods such as distance geometry (DG), dynamical simulated annealing (DSA)
and molecular dynamics (MD) using TRIAD module of SYBYL molecular modelling
software.
Endothelin-1 is the most potent vasoconstrictor discovered to date acting on smooth muscles and the central nervous system. Endothelin-1, which belongs to a new peptide class, is ten fold more potent than the vasoconstrictor angiotensin II, and has extremely long lasting pressor effects. Increasing evidence for the involvement of endothelin in human disease has prompted a major effort in drug design, pharmacological evaluation and structure elucidation. Endothelin-1 is a 21 amino acid peptide whose structure is constrained by two disulphide bridges between residues 1-15 and 3-11. Endothelin has multiple binding sites on various kinds of cell membranes and two endothelin receptor subtypes, termed ETA and ETB, have been identified. In order to find the requirements for the ETB receptor recognition, a series of linear analogues of ET-1 have been synthesised in our laboratory and biological activity was tested at Parke Davis pharmaceuticals. Linear endothelin analogues were synthesised by protecting the methionine and all the cysteines which are liable to oxidation. Methionine can be replaced by leucine without loss of biological activity. The stereochemistry of some of the residues were changed to study the importance of individual residues. Unnatural amino acids were also incorporated to study their effects on the biological activity and the secondary structure of the peptides. During this ongoing project we have found several ETB receptor selective endothelin agonists. Biological activity was tested on rabbit renal artery vascular smooth muscle cells (ETA) and rat cerebellum (ETB). These active peptides show higher ETB agonist activity than ET-1 itself and are the first novel peptidic agonists. The importance of the biologically active structure in determining the specific receptor interactions and eliciting its pharmacological properties has made the three dimensional solution structure of these peptides a subject of intense interest. Biologically active peptides therefore were subjected to solution structure determination by NMR and molecular modelling. The development of these ETB receptor agonists may provide novel therapeutic agents for the treatment of a variety of human diseases. Due to the highly confidential nature of this work, biological activity results can not be presented at this stage.
External Collaborations
- University of Edinburgh
Dr. Ian H. Sadler and Dr. John
A. Parkinson
Molecular structure determination
of bio-active molecules, NMR applications to DNA binding drugs and molecular
modelling, metabolism and bio-fluids
The bioactive conformation of glucose-dependent insulinotropic polypeptide by NMR and CD spectroscopy. Alana I, O'Harte FP, Malthouse JP, Hewage CM., Proteins 2007, 68, 92-99
NMR and Alanine Scan Studies of Glucose-dependent Insulinotropic Polypeptide in Water. Alana I, Parker JC, Gault VA, Flatt PR, O'harte FP, Malthouse JP, Hewage CM. J Biol Chem. 2006 Jun 16;281(24):16370-6.
Alana I., Hewage C.M., Malthouse J.P.G., Parker J.C., Gault V.A., O'Harte F.P.(2004) , NMR structure of the glucose-dependent insulinotropic polypeptide fragment, GIP(1-30)amide, Biochem. Biophys. Res. Comm. 2004, 325, 281-6.
Smith, C.K., Hewage C.M., Fry S.C. and Sadler I.H. (1999), a-D-Maanopyranosyl-(1Æ4)- a-D-glucuronopyranosyl-(1Æ2)-myo-inositol, A New and Unusual Oligosaccharide from cultured rose cells. Phytochemistry, 52, 387
Hewage C.M., Jiang L., Parkinson J.A., Sadler I.H. and Ramage R. (1999), A Linear Endothelin-1 Analogue: Solution Structure of ET-1[Aib1,3,11,15, Nle7] by Nuclear Magnetic Resonance Spectroscopy and Molecular Modelling. Neurochem Int., 35, 35
Anderson R.J., Clark B.P., Hewage C.M., Smith A.I. and Mackay S.P. (1999),
Conformational Analysis of an EP24.15 Inhibitor by NMR and Molecular Modelling
Lett. In Pep Sci., 6, 395
Hewage C.M., Jiang L., Parkinson J.A., Sadler I.H. and Ramage R. (1999), Solution Structure of a Novel ETB Receptor Selective Agonist ET1-21[Cys(Acm)1,15, Ala3,11, Leu7] by NMR Spectroscopy and Molecular Modelling. J. of Pep. Res., 53, 223
Dabos K.J., Plevris J.N., Nelson L.J., Campbell N., Parkinson J.A., Hewage C.M., Sadler I.H., Hayes P.C. (1998), Metabolic Profile of Primary Porcine Hepatocytes in Different Culture Conditions Using 1H Nuclear Magnetic Resonance Spectroscopy, Hepatology, 28, 632
Perrone P., Hewage C.M., Sadler I.H. and Fry S.C. (1998), Na- and Ne-D-Galacturonyl-L-Lysine Amide Bonds: Properties and Possible Occurrence in Plant Cell Walls. Phytochemistry, 49, 1879
Dabos K.J., Nelson L.J., Plevris J.N., Dollinger M.M., Hewage C.M., Sadler I.H., Hayes P.C. (1998), Microgravity Environment in a Rotary Cell Culture System (RCCS) Promotes Cell Aggregation and Maintains Differentiation and Proliferation of Primary Porcine Hepatocytes. GUT, 42(S1) 26
Hewage C.M., Jiang L., Parkinson J.A., Sadler I.H. and Ramage R. (1998), Development of ETB Selective Agonists: Solution Structure of a Linear Endothelin-1 Analogue, ET-1[Cys(Acm)1,15, Ala3, dAsp8, Leu7, Aib11]. J. Biomol. Struct. Dyn., 1998, 16, 425
Hewage C.M., Jiang L., Parkinson J.A., Sadler I.H. and Ramage R. (1998), Solution Structure of an ETB Selective Agonist, ET-1[Cys(Acm)1,15, Ala3, Leu7, Aib11] in CD3OH/H2O by 1H NMR and Molecular Modelling. FEBS Letters, 425, 234
Hewage C.M., Jiang L., Parkinson J.A., Sadler I.H. and Ramage R. (1997), Solution Structure Determination of Endothelin-1 in Methanol/Water by NMR and Molecular Modelling Methods. J. Pep. Sci., 3, 415
Bandara B.M.R., Hewage C.M., Karunaratne V., Wannigama G.P. and Adikaram N.K.B. (1992), An Antifungal Chromene from Eupatorium riparium. Phytochemistry, 31(6), 1983
Bandara B.M.R., Hewage C.M., Jayamanne D.H.L.W., Karunaratne V., Bandara K.A.N.P., Adikaram N.K.B., Pinto M.R.M. and Wijesundara D.S.A. (1990), Biological Activity of Some Steam Distillates from Leaves of Ten Species of Rutaceous Plants. J. Nat. Sci. Coun. Sri Lanka, 18(1), 71
Bandara B.M.R., Hewage C.M., Gamage T.M., Karunaratne V. and Pinto M.R.M. (1989), Antibacterial Activity of Some Sri Lankan Plants. Proc. Sri Lanka Assoc. Advmt. Sci., 45(1), 113
Bandara B.M.R., Hewage C.M., Karunaratne V. and Ratnasooriya W.D. (1989), Spermicidal Activity of Plumbagin and Zerumbone. Proc. Sri Lanka Assoc. Advmt. Sci., 45(1), 114
Bandara B.M.R., Hewage C.M., Fernando I.H.S., Karunaratne V., Adikaram
N.K.B. and Wijesundara D.S.A. (1989), Antifungal Activity of Some Medicinal
Plants of Sri Lanka
J. Nat. Sci. Coun. Sri Lanka, 17(1) 1
Bandara B.M.R., Hewage C.M., Karunaratne V. and Adikaram N.K.B. (1988), Methylester of para-coumaric acid, Antifungal Principle of Rhizome of Costus speciosus. Planta Med., 54(5), 477
Bandara B.M.R., Hewage C.M., Karunaratne V., Bandara K.A.N.P., Jayamanne D.H.L.W., Adikaram N.K.B., Pinto M.R.M. and Wijesundara D.S.A. (1988), Bioactivity of Volatile Constituents of Rutaceae. Proc. Sri Lanka Assoc. Advmt. Sci., 44(1), 212
Bandara B.M.R., Hewage C.M., Karunaratne V. and Adikaram N.K.B. (1988), Antifungal Constituents of Eupatorium riparium. Proc. Sri Lanka Assoc. Advmt. Sci., 44(1), 213
Bandara B.M.R., Hewage C.M., Karunaratne V. and Bandara K.A.N.P. (1988), Insecticidal Activity of Some Sri Lankan Plants. Proc. Sri Lanka Assoc. Advmt. Sci., 44(1), 37
Bandara B.M.R., Hewage C.M., Karunaratne V., Adikaram N.K.B., Pinto M.R.M., Bandara K.A.N.P. and Wijesundara D.S.A. (1987), Bioactivity of Some Medicinal Plants of Sri Lanka. Chemistry in Sri Lanka, , 4(1), 7
Bandara B.M.R., Hewage C.M., Karunaratne V. and Adikaram N.K.B. (1987), An Antifungal Constituent of Costus speciosus. Proc. Sri Lanka Assoc. Advmt. Sci., 43(1), 214
Bandara B.M.R., Hewage C.M., Karunaratne V. and Wijesundara D.S.A. (1987), Phytochemical Studies on Alpinia abundiflora. Proc. Sri Lanka Assoc. Advmt. Sci., 43(1), 233
Conference Proceedings
Hewage C.M., Jiang L., Parkinson J.A., Sadler I.H. and Ramage R. (1997), Determination of the Solution Structures of Modified Endothelin Derivatives by Nuclear Magnetic Resonance Spectroscopy and Molecular Modelling. 13th International NMR meeting, Univ. of Exeter, U.K, July
Hewage C.M., Jiang L., Parkinson J.A., Sadler I.H. and Ramage R. (1995), Conformational Studies and Solution Structure of A Modified Linear Endothelin-1 Derivative; ET-1[Aib3,11, Leu7]. 12th International NMR meeting, UMIST Manchester, U.K, July
Hewage C.M. and Sadler I.H. (1995), The Structure and Full Assignment
of the 1H and 13C spectra of a Biologically Active Glycoside; Ginsenoside
? Rd. 12th International NMR meeting, UMIST Manchester, U.K, July