Biochemistry 4010 Membranes

Biochemistry topics regarding basics of membranes, and proteins within

Glycolipid

A lipid chain consisting of sugars, bound to a lipid in the membrane

GPI-Anchored Protein

Glycosylphosphatidylinositol linked proteins

Peripheral Protein

Protein covalently linked to a lipid embedded into the membrane

Removed via pH or high salt concentrations

Surface peripheral protein

protein sitting on surface of membrane

Removed via pH or high salt concentrations

Integral protein(Amphitropic)

Protein on the interface of the membrane. Can be monotopic (partially in membrane), or polytopic (spanning fully across the membrane). Alpha helix goes across.

Removed with detergents, brings some phospholipids with it

Asymmetry of the membrane

Proteins are asymmetrically oriented on the membrane, with certain parts facing in, and others facing out

Linking to the membrane

Palmitoyl group(16:0) - Cys
Mytristol group (14:0) - N-Gly
Farnesyl group - C-Cys
GPI linked are on the outer face

Positive Inside Rule

Positive charges majorily face the inside of the cell

O-gycosylation, N-glycosylation

Occurs only on the outside of the cell, O-g occurs on Thr, Ser. N occurs on Asn

Hydropathy plots

Tells us approximate number of helices. If even, N and C terminus on same side

Atomic Force Microscopy

Detects surface elevations on a graphical plot. Elevations show lipid rafts

Caveola

Pocket in cell membrane, created by several caveola dimers, including six fatty acyl groups and eight cholesterol moieties. Allows for cells to swell.

SNARE proteins

Pull membranes together during fusion of membranes. V snares are on the Vesicle, T snares are on the Target, and Q snares are induced by calcium

Glucose Transporter

A Uniporter which works via the Rocker mechanism

P type transporter

Active transporter, primary,
Ions only

Autophosphorylation dependent

ABC Casette

Primary transporter, Active, Small molecules. Nucleotide binding domains for 2 molecules of ATP to bind

F/V type

Primary active, ions only, (H+), reversible