Module 3/ Other membrane proteins

Question 1

Amino acids

Answer 1

-Proteins are made of amino acids (polymer of amino acids)

-amino acids are bound together by peptide bonds

-N-terminus=1st position
-C-terminus=last postion

Question 2

Primary structure

Answer 2

Linear sequence of amino acids of a protein. The sequence of amino acids is specific to the function of the protein, its localization, and its interaction with other molecules.

Question 3

Secondary structure

Answer 3

Structure of the protein made of segments that are coiled or folded; determines the proteins shape. Their are two types

-α helices
-β pleated sheets

Question 4

Tertiary structure

Answer 4

3D shape stabilized by interactions between side chains (R groups of the amino acids)

Question 5

Tertiary structure is determined by

Answer 5

-Hydrophobic interaction
-Covalent bonds (disulfide bridge)
-van der waals interactions
-hydrogen bonds
-ionic bonds

Question 6

Quaternary structure

Answer 6

Association of two or more polypeptides (in some proteins only). It is the overall protein structure that results from the aggregation of polypeptide subunits. Each subunit is coded by a single gene.

Question 7

Integral prteins

Answer 7

Typically contain one or more hydrophobic transmembrane helice; ion channels, transporters, receptors

Question 8

Peripheral proteins

Answer 8

Sit on the membrane surface, non-covalently bonded to it. Proteins involved in the membrane sugar, lipid and protein metabolism: oxidase, oxygenase, lipase

Question 9

Lipid-anchored proteins

Answer 9

Covalently bonded to a lipid group of the membrane.

Question 10

Enzyme de conversion de l’angiotensine 2 (ACE2)

Answer 10

-Present on the membrane of cells in the intestine, kidneys, testes, gallbladder, and heart.

-ACE2: plays a role in the lowering of blood pressure by hydrolyzing the angiotensin II (hormone)

-ACE2 is also the port of entry of SARS-Cov2.