ISSN:
1573-5001
Keywords:
1H NMR
;
Bacteriorhodopsin
;
Chymotryptic fragment
;
Secondary structure
;
Assignment
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Chemistry and Pharmacology
Notes:
Summary The conformation of chymotryptic fragment C2 of bacteriorhodopsin (residues 1–71) was studied by 2D1H NMR. The fragment was solubilized in a mixture of chloroform/methanol (1∶1), 0.1 M LiClO4. Most of the resonances in1H NMR spectra of fragment C2 were assigned using phase-sensitive DQF-COSY, TOCSY, and NOESY techniques. To simplify the assignment procedure for overlapping regions of NMR spectra, an analog of fragment C2 with leucines deuterated in β-positions was used. Deuterium exchange rates for amide protons were measured in a series of TOCSY spectra. Two right-handed α-helical regions Pro8-Lys30 and Lys41-Leu62 were identified on the basis of NOE connectivities and deuterium exchange rates. The N-terminal part of the fragment (Ala.2-Gly6) adopts the helical conformation stabilized by 3 hydrogen bonds.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF01875527
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