Analysis

• Like the χ1 rotamers, the same restrictive geometry applies to the χ2 rotamers as well.
• Therefore, the β-branched Isoleucine is not accomodated in this helix and stereochemical configuration.
• The remaining identities also prefer the off-rotamer g- χ1 angle of approximately -100°.
• Leucine is locked in the g- / g- (-60° / -60°) with 99% of the rotameric probability.
• The aromatic residues have a tight range of χ2 flexibility in the t (90°) which is 99% probable for both residues.

Notes

Polar hydrogen placement was optimized for each rotameric state where appropriate (Ser/Thr/Tyr)