Table 4: Calculated dihedral angles (in degrees) of the dipeptides at B3LYP/6-311++G(d,p) level of theory; the gas phase values are given in brackets.

Dipeptides–SC Groups C3–C4–N6–C7O11–C4–N6–H10C3–C4–N6–H10O11–C4–N6–C7 ϕ

Sec-Val–CH(CH3)2176.4 (171.9)−178.8 (−178.9)−0.5 (−0.3)−1.9 (−6.6)19.8 (28.4)−95.8 (−103.7)137.7 (129.3)
Sec-Leu–CH2CH(CH3)2176.4 (172.5)−178.0 (−179.0)0.4 (0.1)−2.0 (−6.7)18.3 (24.8)−73.4 (−91.9)162.9 (142.5)
Sec-Asp–CH2CO2H175.8 (−169.6)−178.9 (169.0)−0.6 (−11.4)−2.6 (10.7)20.6 (33.1)−99.0 (−131.8)135.7 (103.6)
Sec-Ser–CH2OH177.4 (176.5)178.3 (174.1)−3.5 (−7.7)−0.8 (−1.7)21.3 (30.3)−118.4 (−135.7)117.8 (100.6)
Sec-Gln–(CH2)2CONH2178.5 (175.3)179.8 (−177.8)−2.2 (1.2)0.5 (−3.7)22.2 (22.9)−65.4 (−80.9)170.8 (154.5)
Sec-His–(CH2)2C3N2H3178.4 (177.1)177.1 (173.5)−4.7 (−8.3)0.2 (−1.2)23.7 (30.7)−108.5 (−131.4)126.1 (103.9)
Sec-Pyl–(CH2)4NHCO(C5NH8)177.1 (174.7)−178.1 (179.3)0.5 (−2.2)−1.4 (−3.8)18.3 (27.2)−83.0 (−118.5)152.8 (117.4)

MDa4.2 (10.4)2.9 (11.0)4.7 (11.4)2.6 (10.7)

Maximum deviation from expected values.