Beta sheets

Beta sheets are a common secondary structure in proteins that differ from alpha helices, with peptide bonds that are mostly extended. Hydrogen bonds can form between adjacent peptide chains, either inter-chain (between different chains) or intra-chain (within the same chain folding back on itself). Chains can be parallel, running in the same direction, or anti-parallel, running in opposite directions. In parallel sheets, hydrogen bonds are angled, while in anti-parallel sheets, they align vertically. Typically, beta sheets consist of up to 10 strands and are represented as ribbons with arrows pointing toward the C terminal. The side chains in these sheets may be predominantly hydrophobic or hydrophilic, resulting in patches of both types on the same sheet, promoting structural variety depending on hydrogen bond arrangements.