BIOLCHEM 415 Lecture Notes - Lecture 4: Protein Folding, Benzene, Beta Sheet

45 views3 pages

purplebeaver856

26 Jun 2016

School

Department

Course

Professor

For unlimited access to Class Notes, a Class+ subscription is required.

Document Summary

Because of the large benzene ring, tyr is considered a hydrophobic amino acid. The hydrogen bonds between c=o and n-h stabilize the helix. The distance between the start of a turn and the end of a turn in a a-helix is 5. 4 angstroms. The side chains face outside because there is not enough space inside the helix for them. The twist of the helix is right handed. The hydrogen bonds formed between the two sheets are what stabilizes the beta sheets. Side chains face in opposite direction because if they all face out in the same side, this could cause steric hindrance. Hydrogen bonding is different compared to that of the antiparallel sheet. Do not have to know the difference in hydrogen bonding between these two orientations. But a key thing to know is the orientation of the strands. Larger proteins can have both parallel and antiparallel orientation.

Related Questions

1. The level of protein structure that is stabilized primarilyby non-covalent interactions between the side chains within asingle polypeptide chain is refered to as its:

A) primary structure

B) secondary structure

C) tertiary structure

D) quaternary structure

E) none of the above

2. Collagen, a strong fibrous protein found in connectivetissue, bone, and the extracellular matrix, has a structure inwhich three left-handed helices wind around each other to form aright-handed triple helix. The primary structure of collagen has arepeat unit of -(Gly-X-Pro)- Which of the following bonds stabilizethe collagen triple helix? (mark all that apply)

A) Hydrogen bonds between hydroxyproline residues

B) Hydrogen bonds between N-H and C=O

C) Ionic bonds between amino acid side chains

D) Hydrogen bonds between charged amino acids

3. The non-covalent forces that stabilize the Beta-strandconformation of peptides include:

A) H-bonds between amide C=O and amide NH

B) Van der Waals packing between the peptide backbone atoms

C) Van der Waals packing due to side chain interdigitation

D) Only A and B above

E) None of the above

4. What is the approximate length difference of a 22-kDasingle-stranded ?-helical protein segment vs. a 22-kDasingle-stranded ?-strand protein segment? Assume a mean residuemass of 110 Da. Show work.

5. Circular dichroism measurements have shown that the peptidebackbone of poly-l-lysine (KKKKKKK) adopts a random coilconformation at pH 7.0, but becomes ?-helical as the pH is raisedabove 10. This observation is known as the

magentaotter572

BIOLCHEM 415 Lecture Notes - Lecture 4: Protein Folding, Benzene, Beta Sheet

Document Summary

Get access

Related Documents

BIOLCHEM 415 Lecture Notes - Lecture 30: Histone H2B, Semiconservative Replication, Cisplatin

BIOLCHEM 415 Study Guide - Midterm Guide: Reactive Intermediate, Aspirin, Hyperbola

Biology And Biomedical Sciences BIOL 2960 Lecture Notes - Lecture 6: Ionic Bonding, Coomassie Brilliant Blue, Keratin

Related Questions