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Báo cáo khoa học: Solution structure of long neurotoxin NTX-1 from the venom of Naja naja oxiana by 2D-NMR spectroscopy

The NMR solution structures of NTX-1 (PDB code 1W6B and BMRB 6288), a long neurotoxin isolated from the venom ofNaja naja oxiana, and the molecular dynamics simulation of these structures are reported. Calculations are based on 1114NOEs, 19 hydrogen bonds, 19 dihedral angle restraints and secondary chemical shifts derived from 1 Hto 13 C HSQC spectrum. Similar to other long neurotoxins, the three-finger like structure shows a double and a triple strandedb-sheet aswell as some flexible regions, particularly at the tip of loop II and the C-terminal tail | Eur. J. Biochem. 271 4950-4957 2004 FEBS 2004 doi 10.1111 j.1432-1033.2004.04465.x Solution structure of long neurotoxin NTX-1 from the venom of Naja naja oxiana by 2D-NMR spectroscopy Mehdi Talebzadeh-Farooji1 Mehriar Amininasab1 Maryam M. Elmi1 Hossein Naderi-Manesh2 and Mohammad N. Sarbolouki1 1 Institute of Biochemistry Biophysics University of Tehran Iran 2Faculty of Science Tarbiat Modares University Tehran Iran The NMR solution structures of NTX-1 PDB code 1W6B and BMRB 6288 a long neurotoxin isolated from the venom of Naja raja oxiana and the molecular dynamics simulation of these structures are reported. Calculations are based on 1114 NOEs 19 hydrogen bonds 19 dihedral angle restraints and secondary chemical shifts derived from 1H to 13C HSQC spectrum. Similar to other long neurotoxins the three-finger like structure shows a double and a triple stranded b-sheet as well as some flexible regions particularly at the tip of loop II and the C-terminal tail. The solution NMR and molecular dynamics simulated structures are in good agreement with root mean square deviation values of 0.23 and 1 A for residues involved in b-sheet regions respectively. The overall fold in the NMR structure is similar to that of the X-ray crystallography although some differences exist in loop I and the tip of loop II. The most functionally important residues are located at the tip of loop II and it appears that the mobility and the local structure in this region modulate the binding of NTX-1 and other long neurotoxins to the nicotinic acetylcholine receptor. Keywords 2D-NMR long neurotoxins neurotoxin-1 solution structure three-finger peptide. Neurotoxins belonging to Elapidae family are divided 1-3 into two groups of short 60-62 amino acids in length with four disulfide bridges and long neurotoxins 66-74 amino acids with five disulfide bridges . They cause postsynaptic blockage of the nicotinic acetylcholine receptor AChR 4 5 . Despite their functional similarity these peptides have