B2.075 Protein Structure Function: Knowns and Unknowns Flashcards Preview

MCM Test 1 > B2.075 Protein Structure Function: Knowns and Unknowns > Flashcards

Flashcards in B2.075 Protein Structure Function: Knowns and Unknowns Deck (23):
1

compare the exome and transcriptome portions of the genome

exome: all protein coding regions, 2% of genome, constant over lifetime
transcriptome: all transcribed RNA, changes with age and environment

2

how many differences exist between exomes of two unrelated people?

10000

3

what are the classes of protein functions?

chemistry (enzymes), signaling, structure, transport, storage

4

what are the structural classes of proteins?

soluble/globular, fibrillar, integral membrane proteins, intrinsically disordered proteins

5

characterize globular/soluble proteins

hydrophobic inside, hydrophilic outside
2 or more polypeptides
contain alpha helices and beta sheets
1/3 of eukaryotic proteins

6

characterize fibrillar proteins

repeating globular subunits
long twisted fibers

7

what functions are associated with fibrillar proteins?

cytoskeleton and extracellular matrix

8

what are some well known fibrillar proteins?

repeating subunits: actin, tubulin
long polypeptides: collagen

9

characterize integral membrane proteins

hydrophobic on the outside, hydrophilic on inside
25-30% of human exome

10

what is one way to predict membrane spanning regions of amino acid sequences?

hydropathy plots: show hydrophobic stretches in sequence

11

what are functions commonly associated with integral membrane proteins?

receptors, transporters

12

characterize intrinsically disordered proteins

discovered by genome sequencing
30% of proteins in eukaryotes
no core
long repetitive sequences
small sequence islands for binding w a range of partners

13

what functions are commonly associated with intrinsically disordered proteins?

scaffolding, transcription factors, membrane-less organelles
ex: dynein microtubule cargo transport

14

what is a post translational modification commonly associated with intrinsically disordered proteins?

phosphorylation

15

can we predict structure of function of a protein from the sequence?

no lol

16

what are themes apparent from protein families?

conservation, motif, modularity

17

what are conserved residues?

impart common overall structure/function to a group of similar proteins

18

how do missense mutations affect conserved residues?

catastrophic...these residues are important to a group

19

what is a motif?

a conserved short sequence that is associated with a specific function (structure may or may not be known)

20

what are 2 examples of motifs?

zinc finger motif: needed for Zn2+ binding
walker A motif: needed for ATP binding

all common motifs have same sequence pattern and the rest of the protein can vary widely

21

what is protein modularity?

when you mix and match different structure/function classes on one polypeptide

22

how are contiguous domains on a protein connected?

linkers

23

what is the important of domains?

they often have discrete functions which can be identified by deleting other domains from the sequence