BCHM 218 Lecture Notes - Lecture 5: Zipper, Leucine, Beta Barrel
5 May 2018
School
Department
Course
Professor
BCHEM 218 week 2 lecture 2
Proteins
Single or multiple polypep chains
Structure det function
Catalyse biochem rxs, structural, receiving and transmitting chem signals, trans specific ions/molecules across
cellular memb
Primary protein
Primary: linear seq of aa, read from N to C terminus, det shape of protein
Secondary
Secondary: interactions of backbone
B sheet: formed from H bonds b/n backbone of two diff
strands, residues alt w polar side chains creating boundary, R
groups lie on opp sides of sheet to prevent interactions, B
strands run in parallel, anti-parallel or both config
Alpha-helix: most stable w R groups outside helix, each turn=
3.6 aa
B turns: linked via reverse turns (reverses direction and fold in
tertiary structure using 4 residues, 1st residue O H-bonsd w 4th
residue amide forming cis config for tight turns)
Y turns: 3 aa turn, backbone carbonyl and amide group form an
H-bond
Supersecondary
partially stable arrangement of multiple secondary structures
Alpha-helical motifs: interactions b/n alpha-helices when
hydrophobic surfaces face each other, residues spaced every 2-
7 lie on the same side of helix (called a heptad or leucine
repeat)
- Coiled-coil: when 2+ alpha-helices are coiled together,
interacting sections usually contain two heptad repeats,
4-and-3 hydrophobic repeat creates ampiphatic helix if
4-and-5 zipper motif
- Helix-turn-helix: made of 2 alpha-helices, found in
proteins that bind specific DNA seq and
bacteria/eukaryotic transcription factors
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
Catalyse biochem rxs, structural, receiving and transmitting chem signals, trans specific ions/molecules across cellular memb. Primary protein primary: linear seq of aa, read from n to c terminus, det shape of protein. Alpha-helix: most stable w r groups outside helix, each turn= B turns: linked via reverse turns (reverses direction and fold in tertiary structure using 4 residues, 1st residue o h-bonsd w 4th residue amide forming cis config for tight turns) Y turns: 3 aa turn, backbone carbonyl and amide group form an. Supersecondary partially stable arrangement of multiple secondary structures. Alpha-helical motifs: interactions b/n alpha-helices when hydrophobic surfaces face each other, residues spaced every 2- 7 lie on the same side of helix (called a heptad or leucine repeat) Coiled-coil: when 2+ alpha-helices are coiled together, interacting sections usually contain two heptad repeats, Helix-turn-helix: made of 2 alpha-helices, found in proteins that bind specific dna seq and bacteria/eukaryotic transcription factors.
