Bio 2 - translation continued

Exam 2

Post Translation

Processing polypeptides

Folding

For the function of proteins (4 levels - primary, secondary, tertiary, quaternary)

Proteolysis

cut sections of 1 polypeptide - helps proper folding

glycosylation

add sugar to growing chain - cell recognition, long term storage, directions within the cell

phosphorylation

temporarily alter amino acids - activate/deactivate protein, rapid cell responses, proper folding

Parasites + Pathogens Example (blocking transcription)

SARS-CoV-2 : NSP1 is a spike protein which mutates fast and blocks entering transcripts from the small subunit, so it can rush in its own viral mRNA

Certain parts of NSP1 can be blocked, stopping transcription all together

Horse Athletic Performance (don’t burn out of O2)

Horses have amazing endurance because they do not burn out of O2

KEAP1 gene senses reactive O2 species and produces antioxidants to neutralize the O2

In horses the gene has a mutation for an early stop codon, but a second mutation that skips past the early stop codon

2nd mutation lets go of NRF2 (promotes production of antioxidants = amazing endurance

Primary structure

chain/sequence of amino acids

Secondary structure

alpha helixes and beta sheets because of amino acids interacting

Tertiary structure

multiple alpha helixes and beta sheets interacting with each other

Quaternary structure

Independent polypeptides interacting with one another

Post Translational Transport

default location is the cytosol - some proteins are not meant to stay there

Signal sequence

an amino acid tag that tells the growing chain where it needs to go

Translational Pause

proteins can be dangerous if remain in cytosol so a pause in translation will occur, allowing it to be moved to the ER where it can continue