Types of Membrane Proteins

What are the main categories of membrane proteins?

Membrane proteins are classified as integral (transmembrane), lipid-anchored, or peripheral (noncovalently associated with membrane surfaces).

What characterizes an integral membrane protein?

Integral membrane proteins span the bilayer and have hydrophobic regions that interact with the lipid core, often forming alpha helices or beta barrels.

How do single-pass and multi-pass membrane proteins differ?

Single-pass proteins cross the bilayer once, while multi-pass proteins cross multiple times using several alpha helices or beta strands.

What are beta barrel proteins, and where are they found?

are composed of beta sheets forming a cylindrical pore, commonly found in the outer membranes of mitochondria, chloroplasts, and Gram-negative bacteria.

What is a lipid-anchored protein?

are covalently attached to lipid molecules embedded in the membrane, providing stable but reversible membrane association.

What are peripheral membrane proteins?

attach to the membrane surface through noncovalent interactions, often binding to integral proteins or lipid head groups.