In primary structure, I was wondering if the side chains would be exactly opposite each other as shown. It sounded like they would be for a Beta chain but would spiral for an alpha chain. Or if the alpha were stretched so that we could look at its primary structure. The R-groups would behave exactly as you describe for both the helix and beta sheet case. The R-groups just need to be far enough away from eachother to avoid stearic hindrance.
Peptides begin to fold into secondary structure even as they are being translated.
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