Conformational calculations on the Ala14-Pro27 LC1 segment of rabbit skeletal myosin.
In order to define the conformational characteristics of a singular Ala14-Pro27 segment in myosin LC1, conformational calculations were performed using the Simplex algorithm of Nelder and Mead (Computer J. 7 (1965) 308-313) in the ACME program proposed by Tournarie (J. Appl. Cryst. 6 (1973) 309-346). The (Ala-Pro) n = 1 unit was assigned a given conformation x; the conformation energy was then minimized for n = 1 to n = 7 by adjusting structural parameters (angle values). Similarly, 13 different possible conformations were optimized and compared, showing that a (beta 2R)7 conformation is favored by about 20 kcal per mol over the next most probable conformation (C7R)7. In the beta 2R conformation, the (Ala-Pro)7 segment is a wide helix, 15 A in length and 8.65 A in diameter, while the C7R conformation results in a semi-extended structure of 25 A long, with an approximate diameter of 6 A. These characteristics are in agreement with available experimental data and putative functions of the LC1 N-terminus.
Abillon
E
E
CEA-Siège, Paris, France.
Bremier
L
L
Cardinaud
R
R
D000409:Alanine; D000595:Amino Acid Sequence; D000818:Animals; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D008969:Molecular Sequence Data; D015394:Molecular Structure; D009132:Muscles / Q000032:analysis*; D009218:Myosins; D011392:Proline; D011487:Protein Conformation; D011817:Rabbits; D013816:Thermodynamics
D011392:Proline; D009218:Myosins; D000409:Alanine