BISC401 Lecture Notes - Lecture 4: Coiled Coil, Aliphatic Compound, Peptide Bond
24 Sep 2016
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Document Summary
Each strand is a short (5-8 residues) polypeptide segment. Hydrogen bonds in the sheet occur between backbone atoms in separate. They are oriented perpendicularly to the chains of backbone atoms. Beta-sheets can form structural motifs called as beta barrels: beta-barrels are found in membrane-spanning proteins, the interior of the barrel is hydrophilic while the exterior is hydrophobic. Helix bonds occur in closely located amino acids. Strands from single or multiple pol(cid:455)peptides (cid:272)a(cid:374) for(cid:373) -sheets. Located on the surface of a protein, forming sharp bends that reverse the direction of the polypeptide backbone. Stabilized by a hydrogen bond between their end residues. Glycine and proline are commonly found in -turns. Help long polypeptides fold into highly compact structures. Type i: proline reside is at position n+1, the type i turn is stabilized by a hydrogen bond between the carbonyl oxygen of the first n-terminal residue (phenylalanine) and the amide hydrogen of the fourth residue (glycine)
