Membrane Proteins: Structure and Organization

Synonyms

Integral Membrane Protein Structure

Definition

Membrane proteins are those which are integral to, or associated with, the various lipid membranes within and around cells.

Introduction

Membrane proteins are classified by their method of attachment into four main groups: integral, peripheral, partially penetrating, and lipid-anchored. Additionally, integral proteins can be further divided by the type of fold they possess – either alpha-helical or beta-barrel. Traditionally, these proteins have been challenging to study due to their hydrophobic nature and low natural abundance.

Integral Membrane Proteins

Integral membrane proteins constitute a significant proportion of the total protein of most cells and are characterized by insertion through the plasma membrane, resulting in permanent attachment. As such they can only be removed by relatively harsh methods including detergent solubilization or the use of nonpolar solvents. The proteins are surrounded in the membrane by annular...