1-42 Mutations and Proteins Flashcards Preview

MSI Unit I > 1-42 Mutations and Proteins > Flashcards

Flashcards in 1-42 Mutations and Proteins Deck (23):
1

the ramachandran plot shows us

the possible dihedral angles that can be observed in a given amino acid sequence

2

forces that restrict the forms that a protein can take on

protein structure works to maximize favorable charge-charge pairings

satisfy all hydrogen bonds

maximize van der Waals interactions

arrange hydrophobic residues such that they are not interacting directly with water.

All of these forces restrict the forms the protein can take on, influencing its folding heavily.

3

alpha helices

Often contain stretches of hydrophobic residues and act as transmembrane domains.

4

beta sheets

Alternating hydrophobic/hydrophilic residues make them the secondary structure of choice for the proteins of Gram-negatives’ porins; the hydrophobic parts face the membrane, and the hydrophilic parts line the inside of the channel.

5

gram negative porin secondary structure

beta sheets

hydrophobic parts face membrane, hydrophilic line the channel

6

reverse (beta) turn

tight turns in protein

usually contains proline

found in any protein sequence with sharp turns, including multi-pass transmembrane proteins

7

loops

referred to as "irregular structure".

frequently forms binding site for other proteins/substrate.

proteins can share similar scaffolding, different loops sequences give rise to different functions

8

helix-turn-helix

motif found in homeodomains and other DNA binding proteins in all kingdoms of life

9

zinc finger

motif that binds DNA less strongly than helix-turn-helix.

many are used together by transcription factors to bind DNA

10

coiled-coil domain

extremely stable domains found in fibrous proteins like myosin. also observed as DNA-binding domains in trancription factors.

11

problems with folding in vivo

overcome with?

while protein transitions between different intermediates, some intermediates have exposed hydrophobic residues that can interact with neighbors.

overcome with chaperone proteins which cover exposed hydrophobic regions and help folding happen more smoothly

12

Hsp70

used for small proteins

binds proteins and covers exposed hydrophobic patches during folding

13

Hsp60

for larger proteins

takes misfolded proteins into its hydrophobic cavity.

ATPase puts a tight cap on the cavity, which changes it's conformation and reveals charged residues lining the cavity

the protein quickly sequesters its hydrophobic regions within the protein structure

14

Hsp100

uses atp to disassemble harmful protein aggregates

15

role of h-60 and hp70 is mainly to

prevent interactions that cause misfolding or aggregating

16

triple A domain of HP100

uses ATP hydrolysis to thread protein into the cleavage center

17

proteins frequently get mutated in the...

mitochondria - lots of oxidative damage

18

how to treat CF and alzheimers?

enhance ATP rate to stimulate chaperaones

19

treat cancer?

inhibit chaperones. cancer tends to overexpress chaperones

20

protein degredation is regulated by..

ubiquitin/proeasome pathway. subunit will bind, eventually 4 wil link and signal cell degredation. uses enzyme ascade of e1, e2, 3e3.

4 ubiquitin attach, moves to proteosome

21

three parts of proteosome

non-binding portion

22

most proteins are degreaded by the..

ubiquitin-proteosome pathway..

23

describe the proteosome uniquitin pathway

proteins covalently bound to ubiqutin by three enzyme system

1. activating enzyme (activates ubiq)
2. conjugating enzyme (transfers ubiq to protein)
3. ligating enzyme (bonds the ubiquitin to the protein)

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