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Flashcards in Fibrillar Proteins Deck (31):
1

Fibrillar Proteins

insoluble protein that makes up the principal structural proteins of the body. High content of secondary structures that form rod-shaped microfibers (fibrils)

2

Abnormal Collagen cause dysfunction of ....

cardiovascular organs
bone
skin
joints
eyes

3

Amino acid composition of collagen

33% Gly, 10-13% Pro, 10% OH-Pro and 1% OH-Lys + other stuff

4

Enzymes needed to catalyze hydroxilation of Pro and Lys

Lyslyl hydroxylase
Prolyl-4-hydroxylase
Prolyl-3-hydroxylase

5

Hydroxilation enzymes require ....

Fe2+, O2, Vit C, and Alpha-ketoglutatrate

6

Collagen - primary composition, effects of primary composition

involve repeats of -Gly-Pro-Y and -Gly-X-Hyp
- Gly (smallest AA) : will fit into small places
- Pro : helix breaker : No Alpha Helix
- Cross links can be formed

7

Scurvy - cause, symptoms

Ascorbic acid deficiency (Vit C) - poor synthesis of collagen without Co-factor to support collagen enzymes, symptoms diverse

8

Polyproline type II helix

One strand of collagen
Loose, left-handed helix, with three residues per turn

9

Alpha helix

Right-hand coiled or spiral confirmation. Every backbone N-H group donates a hydrogen bond to the backbone C=O group of the amino acid four residues earlier
Secondary structure proteins - Hydrogen bonds hold together

10

Right handed triple helix

Right handed
Low bulkiness of Gly allows COLLAGEN to from

11

Collagen - secondary/tertiary sturtures

Polyprolive type II helix
Right handed triple helix (three member superhelix)
Fibrils

12

How to collagen for fibrils

they can aggregate in quater staggered parallel arrays and cross-link to form fibrils

13

Telopeptides

N and C terminal segmetns of the triple helical region
sites for crosslinking

14

lysyle amono oxidase

Convert Lys groups to ALLYSINE (an aldehyde)
COPPER dependent
collagen + elastin

15

Steps in Biosynth of Collagen

Ribosomes in RER
3 alpha chains translation
Peptide chain a.k.a PRECOLLAGEN
Lumen of RER
Cleavage by signal peptidase
PROCOLLAGEN
Hydroxylation of lysine.proline by hydroxylysine residues
Glycosylation begins
Disulfide bond formation
RER - Triple helical structure
PROCOLLAGEN
Shipped to GA
Glycosylation complete
Secretion by exocytosis (into ECM)
Propeptides cleaved
TROPOCOLLAGEN together form COLLAGEN FIBRILS together form COLLAGEN FIBERS
Maturation (intra/inter crosslinks)

16

Collagenases - def, action

Matrix metalloprotienases (MMP's) that catalyze hydrolysis of collagens, which typically have long half lives
Clips collagen, triple helix unwinds and further degrades by gelatinases

17

Collagen - types

Fibrillar : I-III, V, XI
Network Forming : IV
Fibirl associated : IX, XII

18

Ostegensis Imperfecta - def., types (severity)

genetic disorder of collagen type I (mutation in chain alpha 1 or alpha 2)
OI type 1 - mild and common (type IA and IB)
OI type II - most severe - death in utero
OI type III - progressively deforming - most severe past infancy
OI type IV - moderately severe - variety

19

Ehlers-Danlos Syndrome

Group of connective tissue disorders

20

Elastin - def., compostion, sturcture

Provides elasticity to tissues, fibrous, insoluble to water
Lacks regular secondary structure but contains an UNORDERED coiled structure
Composed of allysines (secondary)
Desmosine and Isodesmosine (tertiary)- covalently crosslink chains

21

Cytoskeleton - composed of

microtubles, intermediate filaments and microfilaments

22

Microfilament - composed of,

Actin
Myosin

23

Microtubles - composed of, affected by (action)

alpha and beta tubilin
Colchine - dissaemble microtubules
Taxol - inhibit microtuble formation through binding (cell cylce specific)
Vince Alkaloids - Inhibit microtubles formation
Taxanes and Epothilones - Enhance microtuble stability

24

Kinesin and Dyenins

K - move vesicles to the + end of microtubules
D - move vesicles to the - end of microtubules

25

Intermediary filament - def., e.g.

Exclusively structural
Keratin (hard and soft)

26

Keratin - structure

Coiled coils - a dimer of alpha helices

27

OI type I

few to 100 fractures, no bone deformity, normal stature, , normal teeth, blue scelra

28

OI type II

Perinatal, lethal, dark blue sclera

29

OI type III

Severe, lots of bone deformity, short stature, bad teeth, blue sclera, frequent hearing loss

30

OI type IV

moderate to mild, some bone deformity, some hearing loss, some short stature, normal to gret sclera

31

Types of OI mutations - explanations

Null allele = nulceotide deletion of frameshift = incorrect mRNA = low alpha 1 collagen = OI type 1
Structural mutation - single nucleotide change for Gly = new AA = variying problems = OI type II, III, IV