Beta Domain Structures

Beta barrel - UDUDUDUD

UDUDUDUD anti-parallel beta barrel

example is RBP - retinol (vitamin A) binding protein. Hydrophobic core for hydrophobic retinol molecule.

example is SOD - superoxide dismutase

alternating hydrophobic (inside) and hydrophilic (outside) residues in beta strands

propeller - up-and-down β sheets

Neuraminidase. part of flu virus (HxNx), cuts sialic acid so new virus can leave the infected cell. H (hemeglutanin) holds onto the cell's sialic acid. flu virus at khan academy

Subunit is 6 x DUDU 4 β sheet in propeller shape. 6 propeller blades.

Active site is at the top of the subunit. Loop regions create a funnel shape.

tetramer

beta barrel - with greek key

anti-parallel 8 strand barrel, but NOT sequential UDUD. 32147658

like a greek key. Next strand is n+3 instead of n+1.

γ crystallin. monomeric, 2 barrels.

like a barrel composed of 2 greek keys, but really 2 sheets as H bond missing between 3-2, 6-7. Start from bottom. 3214

2 x domain ( 2 x 2 x greek key)

beta barrel - jelly roll

draw cylinder + string

8 antiparallel again

draw 8 stands around barrel, start at 1U. then link across in perpendicular direction. loops never cross, but are parallel.

link top 1 to adjacent, bottom 1 to adjacent.

not actually a barrel (not enough H bonds)

flu hemagglutinin has a stalk (HA2) with a globular jelly roll (HA1) which is the sialic acid binding site. trimer.

HA2 is hidden, until low pH changes stalk stretches up (loop -> helix) and and fusion peptide works on the target membrane.

beta helix

prism of strands. Calcium binding.