Biochemistry week3,4,5 Flashcards
What is the extracellular matrix
A network of macromolecules in the extracellular space, forming a 3 dimensional framework for tissue and organs.
What is the role of the extracellular matrix
It regulates cellular processes
What is the extracellular matrix composed of?
- Fibrilliar proteins
- Non collagenous glycoproteins
- proteoglycan
What are the major proteins in the Extracellular matrix
collagen
How are collagens classified?
As fibrillar and non-fibrillar
What is the function of collagen fibrils?
It provides flexibility and high tensile strength
What is the primry structure of proteins?
This is the linear sequence of amino acids in a protein
What is the secondary structure of proteins?
This refers to the folding of the polypeptide chain, which is stabilised by hydrogen bonding between carbonyl and amide group
Name the 2 types of secondary structure
- Alpha helix
- Beta pleated sheet
Describe the alpha helix structure
- Rod like, righthanded spiral, coiled structure
- Each amide carbonyl group in the helix forms a hydrogen bind with an amide hydrogen for residues away
Describe the beta pleated sheet structure
- Forms lateral hydrogen bonds between the peptide bonds
- It is an extended structure with tetrahedral C-C binds creating a pleated shape
- It can be arranged in parallel or antiparallel
- Beta turns or bends allow the polypeptide to reverse direction
What is the tertiary structure
A 3 dimensional conformation of a protein
What is the tertiary structure stabilised by?
- It is stabilised by side chain interactions:
- Disulfide
- Hydrogen bonds
- Salt bridges
- Hydrophobic interactions
Where do salt bridges form in the tertiary structure
- They form between the oppositely charged amino acids
Name hydrogen donors and acceptors in the tertiary sturtcure and their role
hydrogen donors:
- Tryptophan
- Arginine
hydrogen acceptors:
-Asparaginine
- Glutamine
They contribute to the structure
What do denaturants do to the tertiary structure and name one
- Urea
They distrupt the secondary and tertiary structure by blocking the stabilising interactions
What is the quaternary structure?
refers to the assembly of 2 or more peptide chains(subunits) in a protein
What are the subunits in the quaternary sturtcure held together by?
Covalent and non-covalent interaactions on their surface
In the quarternary structure what are multisubunit proteins with multiple chains described as?
- Dimeric
-Trimeric
-Multimeric
Explain the structure of hemoglbin
- Has a terameric structure, with 2 a and b globin chains, each with a non covalently bonded heme group
What is myoglobin
- Single globin polypeptide chain
What happens in the secondary structure of mammalian globins
-It has a high alpha helix content, organised into eight segments form a spherical globin fold
What is the tertiary structure of mamalian globins?
- A helix a tightly packed in a spherical structure kown as the globin fold
What is the structure if the Heme prosthetic group?
- It is a porphyrin molecle with an iron atom at its center which binds to oxygen
- It is plantar and mostly hydrophobic