The Ramachandran plot is a vital tool for analyzing the conformational angles (ϕ-phi and ψ-psi) of the amino acid residues in protein structures. It helps in understanding the sterically allowed and disallowed regions for polypeptide backbones. Considering the constraints of steric hindrance and optimal hydrogen bonding, which of the following statements is accurate regarding the Ramachandran plot?
1
The densely populated regions in the Ramachandran plot solely indicate the allowed conformations for glycine, as it has the smallest R-group, hydrogen, which minimizes steric hindrance.
2
β-strands are typically found in the positive ϕ and negative ψ quadrant, reflecting their unique hydrogen bonding pattern and chain extension.
3
Left-handed α-helix conformations are more favored over right-handed α-helix conformations due to lower steric clashes in the backbone.
4
The forbidden regions of the Ramachandran plot are a result of angle combinations where the carbonyl oxygen of one amino acid would spatially clash with the β-carbon (where present) of the adjacent residue.