ISSN:
1573-5001
Keywords:
Proline
;
Conformation
;
Protein
;
Solution structure
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Chemistry and Pharmacology
Notes:
Summary Three different conformations of proline rings in a protein in solution, Up, Down and Twist, have been distinguished, and stereospecific assignments of the pyrrolidine β-, γ- and δ-hydrogens have been made on the basis of 1H-1H vicinal coupling constant patterns and intraresidue NOEs. For all three conformations, interhydrogen distances in the pairs α-β3, β3-γ3, β2-γ2, γ2-δ2, and γ3-δ3 (2.3 Å) are shorter than those in the pairs α-β2, β2-γ3, β3-γ2, γ2-δ3, and γ3-δ2 (2.7–3.0 Å), resulting in stronger NOESY cross peaks. For the Up conformation, the β3-γ2 and γ2-δ3 spin-spin coupling constants are small (〈3 Hz), and weak cross peaks are obtained in a short-mixing-time (10 ms) TOCSY spectrum; all other vicinal coupling constants are in the range 5–12 Hz, and result in medium to strong TOCSY cross peaks. For the Down form, the α-β2, β2-γ3, and γ3-δ2 vicinal coupling constants are small, leading to weak TOCSY cross peaks; all other couplings again are in the range 5–12 Hz, and result in medium to strong TOCSY cross peaks. In the case of a Twist conformation, dynamically averaged coupling constants are anticipated. The procedure has been applied to bovine pancreatic trypsin inhibitor and Cucurbita maxima trypsin inhibitor-V, and ring conformations of all prolines in the two proteins have been determined.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00211775
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