Study BMB 401H Chap 8 Flash Cards

 
Pile Management Card
BMB 401H Chap 8

loading
a-b barrels (the TIM fold)
-This fold has 8 stranded parallel b barrel concentric with 8 outer a helices.
-active sites on C terminal side of b strand loop regions
b barrels
-Diverse group
-4 to over 10 antiparallel strands
-typically 2 b sheets that pack against each other
-looks like barrel
The globin fold
-Globin fold found in myoglobin, hemoglobin
-8 a helices bundle
-forms a pocket for the active site (such as heme)
-Protects heme from contact with other heme
a-a motifs
4 a helices in a bundle
-residues contacting each other in the bundle are hydrophobic
b-a-b motif
-Connection between strands of parallel b-sheets are frequently made by a-helix
-motif has b-strand, loop, a-helix, loop and b-strand
-common in parallel b-sheets
Helical axis usually parallel with that of b-sheet
-Helix and sheet pack hydrophobic residues
-loops often active sites
-right handed
Hairpin b motifs
This motif is two adjacent antiparallel strands joined by a loop. Called either a hairpin or a b-b unit
Supersecondary structures
-Building blocks for proteins
bab motif
b hairpin motif
aa motif
Greek key motif
Side chain location varies with polarity:
-tendency to hide hydrophobic residues
-Val, Leu, Ile, Met and Phe in interior
-When in interior, always hydrogen bonded.
-H bond ‘neutralizes’ charge so that it can go to interior
Globular proteins
-spherical molecules
-Some proteins have just a helix (myoglobin), others have a large proportion of b sheets (concanavalin A).
Most proteins have significant amounts of both (carbonic anyhydrase.
Place this card into pile: