Proteins - w2 Flashcards
What’s an example of a transport protein?
hemoglobin
What’s an example of a storage protein?
ferritin
Which proteins are functional and water-soluble?
globular proteins
Which proteins are structural, linear polymers with repeating units?
fibrous proteins
Which proteins are a subunit of globular proteins and can cross lipid membranes?
transmembrane proteins
Which proteins are a subunit of globular proteins and has domains for histones?
DNA-binding proteins
What are the four levels of protein structure?
primary (single polypeptide chain), secondary (helix or sheet), tertiary (folds)m quaternary (1+ tertiary proteins)
What kind of reaction occurs in the binding of amino acids to make a polypeptide chain?
condensation reaction
What does the N-terminal consist of?
the amino group
What does the C-terminal consist of?
carboxyl group
What’s another name for the terminals?
residues
What stabilizes a-helices?
hydrogen bonds between NH and CO groups (4 AAs apart)
What is the helix breaker and cannot form into a-helix because the NH is already bonded?
proline
How does a parallel beta sheet bond?
one AA residue to two AA residues on the other strand
How does an anti-parallel beta sheet bond?
one AA residue to one AA residue
What do we call beta turns that connect strands of antiparallel b-sheets?
beta loop (hairpin bend) held together by a stable hydrogen bond
What do we call the physically independent regions on a tertiary structure?
structural domains
What bond in a tertiary confirmation is between positively and negatively charged AAs?
ionic bonds
What bond in a tertiary confirmation can occur between two cysteine residues?
disulfide bond
Which domain of a transmembrane tertiary protein is the binding site for hormones?
ligand-binding domain (Extracellular)
Where do we find the G-protein binding domain in a transmembrane protein?
intracellular domain
Which post-translational modifications occur intracellularly?
phosphorylation
Where do glycosidic bonds occur?
extracellularly
What are the structure of soluble globular proteins?
charged aa’s are on surface in contact with water, non-polar (hydrophobic) aa’s in the cor