4 ms·
> while peptides usually are too short to have a defined fold. That's not strictly true. My PhD project has looked at an entire class of peptides that are know
by glenvdb 7y ago
> while peptides usually are too short to have a defined fold.
That's not strictly true. My PhD project has looked at an entire class of peptides that are known to fold in to alpha-helices when bound to a cell membrane e.g. https://www.rcsb.org/structure/2k9b https://www.rcsb.org/structure/2k9b.
There are many others that are known to fold into beta-sheets too.
- gilleain 7y agoFair, but I would not really call a single helix a 'fold', either! Ok, so I'm playing with definitions here a bit. Clearly 2k9b adopts a helical structure so it is 'folded' in some sense. However it has no tertiary structure. Structural proteins like collagen are different again. They have a simple fold that could be described as quaternary (multichain), although that is again an abuse of terminology. There are also some small proteins (peptides?) held together by disulphide links that have no secondary strucure to speak of. I think these are Class 4 in CATH, but I do not remember. What is an example of a beta-sheet peptide? Amyloid is beta, I thought, but sheets are not normally stable outside sandwiches, barrels, etc
- flobosg 7y ago> What is an example of a beta-sheet peptide? WW domains[1] fold stably into a three-stranded sheet. Also, not strictly a sheet, but beta hairpin motifs (e.g. tryptophan zippers[2]) are known to be stable isolated from their parental domains. [1]: http://www.rcsb.org/structure/5VTJ http://www.rcsb.org/structure/5VTJ [2]: http://www.rcsb.org/structure/1LE0 http://www.rcsb.org/structure/1LE0