Extracellular Matrix: Collagen, Glycoproteins, and Proteoglycans

4 tissues collagen I and III are found in

Gingiva, periodontal ligament, cementum, alveolar bone

Collagen VI is unique to what tissue?

gingiva

Collagen in anchoring fibers and upper periodontium turn over every ______

24 hours

A higher percentage of what collagen fiber type in the periodontal ligament increases flexibility?

type III

What are PTD and ITD?

peritubular dentin and intertubular dentin

which dentin type is harder? Why?

peritubular; it is more mineralized

What cell type secretes dentin?

odontoblasts

What organelles are abundant in odontoblasts?

rough ER, golgi, secretory vesicles

Where is collagen not found in abundance? What has a similar role its place?

enamel; amelogenin

What percentage of collagen is glycine?

33%

Collagen has a high abundance of ______, meaning _____

proline; there are no alpha helix structrues

The repeat in collagen is every ____ amino acids starting with _____ and each individual turn is ____ handed

3; glycine; left

The diameter of collagen is ____ an alpha helix

smaller

When the three coils of collagen come together, the wrap in a _____ handed fashion

right

hydroxylation of proline and occasionally lysine residues contributes to ______ _____

thermal stability

Type IV collagen has a _____-____ ____ structure and is found in the ___ ____

sheet-like mat; basil lamina

Collagen enters the ER in what fashion?

co-translationally

Collagen begins to fold where?

in the lumen of the ER

Where does hydroxylation of proline/lysine occur in collagen?

co-translationally

What do the hydroxylation enzymes for collagen require?

O2, Fe2+, a-ketoglutarate, vitamin C

What is a clinical condition resulting from failure of proline hydroxylation?

scurvy

C-terminal propieces facilitate______, prevent_______ and are later _____

triple helix formation; premature aggregation inside the cell; removed

Where on the collagen polypeptides are propieces found?

Both the N and C termini

Staggered arrangement of of triple helices leave gaps that serve as _____ points for _____ precipitation and mineralizatoin of teeth and bone

nucleation; CaPO4

Connective tissue under the basal lamina contains types ____ and _____ collagen

I; III

Type 4 collagens associate through ____ domains. They form a ____ - shaped multimer

NC1; flat

The presence of HyPro increases temperature needed to denature collagen from ___ to ___

24; 39

What increases thermal stability of collagen past 39?

covalent cross linking of collagen triple helices

what enzyme facilitates collagen crosslinking and what does it require?

lysine amino oxidase; copper

Cause of osteogenesis imperfecta type I

decreased synthesis of type I collagen

Causes of osteogenesis imperfecta type II/ dentineogenesis imperfecta type I

loss of functionmutatoins in triple helical region of collagen type I

Causes of dentineogenesis imperfecta type II/dentine dysplasia

DSPP; dentine sialophosphoprotein

Causes of amelogenesis imperfecta? What does it lead to?

faulty amelogenin that forms plaques. Affects the mineralization process that occurs when it is replaced. Leads to brittle enamel

Functions of carbohydrates

metabolic fules, endergy storage, structural framework, components of nucleic acids

Carbs can be used to modify _____

proteins

Stereochemical designation of carbs arises from the asymmetric ______ in relation from the ______ croup

furthest; carbonyl

IF the a hydroxl/O linkage is up, it is in the _____ configuration

beta

If the if the hydroxy groups are down, up, down, up starting at the 2 carbon, the molecule is _____

glucose

If the hydroxyl group on the a Carbon is down, it is in the _ configuration

alpha

galactose is a ____ epimer of glucose

C4

mannose is a ___ epimer of glucose

C2

free aldehydes can reduce _____ to ____, makes glucose reducing a sugar

Cu++; Cu+

how to recognize a-D-Fructofuranose

the CH2OH groups flanking the O are up

Sialic acid is an exotic ____, its abbreviation is _______

sugar; NANA

Importance of glycosylation of carbs (2)

no longer in equilibrium with straight chain form, non-reducing

anomeric carbonds can react with amino groups to form N-glycosidic bonds

Lactose is a _____ sugar. it has a ____ end and a ___ end

reducing; nonreducing; reducing

sucrose is a _______ sugar

non-reducing

glucose + galactose =

lactose

glucose + fructose =

sucrose

glucose + glucose =

maltose

Many proteins that enter the secretory pathway are modified by _______

glycosylation

Proteins are directed to the secretory pathway by a signal at their ____ terminus

amino

What is the structure of N-linked glycosylation

oligosaccharides linked to ASN residues in the sequence context Asn-X-Ser or Asn-X-Thr

main sugar composition of the N-terminal oligosaccharide

glucose, manose, acetyl-glucose

Dolichol is a ______. This means it is going to be a _____ environment, likely associated with the _____

lipid; hydrophobic; membrane

______ ______ recognizes the sequence context of dolichol

oligosaccharide transferase

The complex class is defined by the presence of _______ (______ _____)

NANA; sialic acid

Core oligosaccharide is added _______

co-translationally

Dolichol is used to _______

anchor the core oligosaccharide to the ER membrane

Glycosylation occurs through an ordered series of processing reactions that involves both _____ and _____ of carbohydrates

trimming; addition

Glycosylation protects proteins from _____ and function in molecular _____

degradation; recognition

glycosaminoglycans are composed entirely of ______, and are made of repeating ______.

sugars; dimers

In glycosaminoglycans, one position is commonly an _____ _____, and one or sometimes both postitions are sugar acids with _____ or _____ acid functional groups

amino sugar; carboxylic; sulfuric

Diseases that result in defects in glycosaminoglycans result from _______

mucopolysaccharidoses