NMR Structure Determination Of Toxin b

• Main Authors: Shi-Shung Peng, 彭世熊
• Other Authors: Yu Chin
• Format: Others
• Language: zh-TW
• Published: 1996
• Online Access: http://ndltd.ncl.edu.tw/handle/92791648917678551684

碩士 === 國立清華大學 === 化學學系 === 84 === The solution structure of Toxin b, a long neurotoxin ( 73 no acids and five disulfides) , from the venom of Ophiophagus hannah( King Cobra) has been determined using 1H NMR and modeling. The structures were calculated using 415 distance constraints and 52 dihedral angle restraints. The average atoms RMSD between the twelve refined structures and the mean structure is 0.7 ?for the backbone heavy atoms, and 3.1for all the heavy atoms. The protein consists of a core region from which three finger like loops extend outwards. The secondary structure includes a short double and a triple antiparallel b sheets. Comparison with the solution structures of other long neurotoxins indicates that the structure of toxin b is quite similar to previously reported long neurotoxin structures but clear local structural differences are observed in regions thought to be for binding of neurotoxins to the acetylcholine receptor (AChR). Loop II, which is important for the binding of the toxin to the acetylcholine receptor is shorter in toxin b as compared to the other long neurotoxins and the tip of Loop II has a well defined local structure.