Structure determination of the three disulfide bond isomers of α-conotoxin GI:: A model for the role of disulfide bonds in structural stability

被引:148
作者
Gehrmann, J [1 ]
Alewood, PF [1 ]
Craik, DJ [1 ]
机构
[1] Univ Queensland, Ctr Drug Design & Dev, Brisbane, Qld 4072, Australia
基金
澳大利亚研究理事会;
关键词
alpha-conotoxin; disulfide bond isomer; nicotinic acetylcholine receptor; nuclear magnetic resonance; peptide structure;
D O I
10.1006/jmbi.1998.1701
中图分类号
Q5 [生物化学]; Q7 [分子生物学];
学科分类号
071010 ; 081704 ;
摘要
The three possible disulfide bonded isomers of alpha-conotoxin GI have been selectively synthesised and their structures determined by H-1 NMR spectroscopy. alpha-Conotoxin GI derives from the venom of Conus geographus and is a useful neuropharmacological tool as it selectively binds to the nicotinic acetylcholine receptor (nAChR), a ligand-gated ion channel involved in nerve signal transmission. The peptide has the sequence ECCNPACGRHYSC-NH2, and the three disulfide bonded isomers are referred to as GI(2-7;3-13), GI(2-13;3-7) and GI(2-3;7-13). The NMR structure for the native isomer GI(2-7;3-13) is of excellent quality, with a backbone pairwise RMSD of 0.16 Angstrom for a family of 35 structures, and comprises primarily a distorted 3(10),, helix between residues 5 to 11. The two non-native isomers exhibit multiple conformers in solution, with the major populated forms being different in structure both from each other and from the native form. Structure-activity relationships for the native GI(2-7;3-13) as well as the role of the disulfide bonds on folding and stability of the three isomers are examined. It is concluded that the disulfide bonds in alpha-conotoxin GI play a crucial part in determining both the structure and stability of the peptide. A trend for increased conformational heterogeneity was observed in the order of GI(2-7;3-13) < GI(2-13;3-7) < GI(2-3;7-13). It was found that the peptide bond joining Cys2 to Cys3 in GI(2-3;7-13) is predominantly trans, rather than cis as theoretically predicted. These structural data are used to interpret the varying nAChR binding of the non-native forms. A model for the binding of native GI(2-7;3-13) to the mammalian nAChR is proposed, with an alpha-subunit binding face made up of Cys2, Asn4, Pro5, Ala6 and Cys7 and a selectivity face, comprised of Arg9 and His10. These two faces orient the molecule between the alpha and delta subunits of the receptor. The structure of the CCNPAC sequence of the native GI(2-7;3-13) is compared to the structure of the identical sequence from the toxic domain of heat-stable enterotoxins, which forms part of the receptor binding region of the enterotoxins, but which has a different disulfide connectivity. (C) 1998 Academic Press Limited.
引用
收藏
页码:401 / 415
页数:15
相关论文
共 65 条
[1]   AMINO-ACID-SEQUENCE OF A HEAT-STABLE ENTERO-TOXIN PRODUCED BY HUMAN ENTERO-TOXIGENIC ESCHERICHIA-COLI [J].
AIMOTO, S ;
TAKAO, T ;
SHIMONISHI, Y ;
HARA, S ;
TAKEDA, T ;
TAKEDA, Y ;
MIWATANI, T .
EUROPEAN JOURNAL OF BIOCHEMISTRY, 1982, 129 (02) :257-263
[2]  
ALMQUIST RG, 1989, INT J PEPT PROT RES, V34, P455
[3]  
Aprison MH, 1996, J NEUROSCI RES, V43, P127
[4]   Conformations and dynamics of the essential cysteinyl-cysteine ring derived from the acetylcholine receptor [J].
Avizonis, DZ ;
FarrJones, S ;
Kosen, PA ;
Basus, VJ .
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 1996, 118 (51) :13031-13039
[5]   MLEV-17-BASED TWO-DIMENSIONAL HOMONUCLEAR MAGNETIZATION TRANSFER SPECTROSCOPY [J].
BAX, A ;
DAVIS, DG .
JOURNAL OF MAGNETIC RESONANCE, 1985, 65 (02) :355-360
[6]   CORRELATION OF PROTON AND N-15 CHEMICAL-SHIFTS BY MULTIPLE QUANTUM NMR [J].
BAX, A ;
GRIFFEY, RH ;
HAWKINS, BL .
JOURNAL OF MAGNETIC RESONANCE, 1983, 55 (02) :301-315
[7]  
BENHAM CJ, 1993, PROTEIN SCI, V2, P41
[8]   THE ACTIVE-SITE OF METHANOL DEHYDROGENASE CONTAINS A DISULFIDE BRIDGE BETWEEN ADJACENT CYSTEINE RESIDUES [J].
BLAKE, CCF ;
GHOSH, M ;
HARLOS, K ;
AVEZOUX, A ;
ANTHONY, C .
NATURE STRUCTURAL BIOLOGY, 1994, 1 (02) :102-105
[9]   CHARMM - A PROGRAM FOR MACROMOLECULAR ENERGY, MINIMIZATION, AND DYNAMICS CALCULATIONS [J].
BROOKS, BR ;
BRUCCOLERI, RE ;
OLAFSON, BD ;
STATES, DJ ;
SWAMINATHAN, S ;
KARPLUS, M .
JOURNAL OF COMPUTATIONAL CHEMISTRY, 1983, 4 (02) :187-217
[10]   3-DIMENSIONAL STRUCTURE OF PROTEINS DETERMINED BY MOLECULAR-DYNAMICS WITH INTERPROTON DISTANCE RESTRAINTS - APPLICATION TO CRAMBIN [J].
BRUNGER, AT ;
CLORE, GM ;
GRONENBORN, AM ;
KARPLUS, M .
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA, 1986, 83 (11) :3801-3805