Fibrous Proteins Flashcards
characters of fibrous proteins
dominating kind of secondary structure
long, narrow rod-like
low water solubility
role for tissue/cellular architecture
Collagen structure
most abundant protein in body
rigid, insoluble
alpha chain has glycine - x - y repeats
type 1 collagen
skin, bone, tendons, cornea
type 2 collagen
cartliage, intervertebral disks, vitreous body
type 3 collagen
blood vessels, dermis, lymph nodes, early would repair
type 4 collagen
basement membranes
especially kidney
type 5 collagen
most interstitial tisse
associated with type 1
three biosynthesis processes for collagen
osteoblasts
chondroblasts
fibroblasts
outside of the RER is where collagen is secreted then cleaned up on the edges
process of collagen production
precursor alpha chain in ER lumen
procollagen forms triple helix with loose ends in ER lumen
secretion out of cell via procollagen peptidase
Tropocollagen is then assembled with collagen fibrils outside of cell
collagen fibrils form into collagen fiber
biosynthesis of collagen
pro alpha chains
hydroxylation where proline and lysine residues are hydroxylated with Vitamin C
glycosylation occurs with disulfide bonds, secretes as procollagen
extracellular removal of terminal extensions, creating tropocollagen
collagen fibril overlap to create stronger structure
cross linking by lysyl oxidase = tensile strength
hydroxlyation at Proline and Lysine
requires ascorbic acid (Vitamin C) as coenzyme
interchain H bond formation and stable a triple helix
Scurvy
vitamin C deficiency
bruises, petechiae, gum disease, loosen teeth
do to poor diet
what is needed for cross linking by lysyl oxidase
Copper (cofactor)
PLP/B6 Vitamin (coenzyme)
the more cross links there are means more stiffer as age
Disease collagen type 1
osteogenesis imperfecta, EDS
Disease collagen type 3
EDS (vascular)
Disease collagen type 4
Alport’s syndrome
goodpasture’s syndrome
Disease collagen type 5
EDS
Osteogenesis imperfecta
brittle bone, blue sclera
Menke disease
steely hair, x link recessive with deficient cross linking and copper deficeincy
composition of elastin
small nonpolar AA
rich in proline and lysine
little OH-Pro, OH-Lys
rubber like and connective tissue for elastic ligament
synthesis of elastin
tropoelastin combine with microfibrillar protein including fibrillin 1
elastin cross linking
catalyzed by lusul oxidase where 4 lysine are cross link into desmosine
desmosine is all eleastic properties
keratin made up of
two pairs of alpha helices to form protofilament
these form intermediate filament
these form microfibrils then macrofibrils
What makes up hair shape?
cysteine bonds in keratin
Epidermolysis bullosa simplez
blister formation at dermoepidermal junction
due to mutation on gene for Keratin 5/14
