Lecture 56 Flashcards
Collagen and Elastin function in the ____ ____ matrix, which means they are made within the cell and then secreted out.
They function in the EXTRA CELLULAR MATRIX.
Collagen genes are located ______ the genome.
They are located THROUGHOUT the genome.
All collagens have _____-helical structure with the AA ___ in every third position.
Triple-helical structure with GLYCINE at every third position.
Gly-X-Y structure of collagen is observed where X is usually ____ and Y is either hydroxy_____ or hydroxy_____.
X is usually PROLINE, and Y is either hydroxyPROLINE or hydroxyLYSINE.
In the process of making collagen in the cell, the mRNA is translated in the _____, then select _____ and _____ residues are hydroxylated, and then only _____ _____ residues are glycosylated. Next, these pro-alpha chains assemble, forming inter and intrachain ______ bridges at the _____-terminal. The triple helix structure is then formed by “zipper-like” folding from the _____-terminal to the _____-terminal, and the procollagen molecule is secreted into the ECM. There, the termini are cleaved, and the collagen molecules self-assemble to form cross-linked _______.
Collagen mRNA is translated in the CYTOSOL, then select PROLINE and LYSINE residues are hydroxylated, and then only HYDROXYLYSINE residues are glycosylated. Next, these pro-alpha chains assemble, forming inter and intrachain DISULFIDE bridges at the C-terminal. The triple helix structure is then formed by zipper-like folding from the C-terminal to the N-terminal, and the procollagen molecule is secreted into the ECM. There, the termini are cleaved, and the collagen molecules self-assemble to form cross-linked FIBRILS.
The hydroxylation of proline and lysine residues requires two cofactors, _____ and _____.
Requires cofactors Fe2+ and VITAMIN C.
Lysyl _____ is the enzyme responsible for cross-linking collagen molecules, which requires _____ as a cofactor.
Lysyl OXIDASE is the enzyme responsible for cross-linking collagen molecules, which requires COPPER as a cofactor.
Copper deficiency leads to ______ disease, whereas Copper buildup leads to ______ disease.
Cu deficiency leads to Menke’s disease, and Cu buildup leads to Wilson’s disease.
OI (osteogenesis imperfecta) type I is the ____ severe, where as type II is the _____ severe.
Type I is the LEAST severe, whereas type II is MOST severe.
Type II, III, and IV OI arise from substitutions in the gene for ____1A1 or ____1A2 which results in the change from _____ to another AA with a bulky side chain. This prevents correct folding into the triple helix form.
Arise from substitutions in the gene for COL1A1 or COL1A2 which results in the change from GLYCINE to another AA with a bulky side chain.
Severity of the 4 types of OI is in this order ___>___>___>___
II>III>IV>I
Whereas Types II, III, and IV OI arise from point mutations, Type I OI arises from a ______ mutation, so only a little collagen is made while most of the mRNA is degraded.
Type I OI arises from a NONSENSE mutation.
____ coloring in sclera is characteristic of patients with OI.
BLUE coloring of sclera is characteristic of OI.
Unlike Collagen, elastin has only a little hydroxy_____ and no hydroxy_____.
Elastin has only a little hydroxyPROLINE and no hydroxyLYSINE.
In the ECM, elastin interacts with _____. Mutations in _____ lead to Marfan syndrome, which shows a(n) _____ dominant mode of inheritance linked to the ____ gene on chromosome 15.
Elastin interacts with FIBRILIN. Mutations in FIBRILIN lead to Marfan syndrome, which shows an AUTOSOMAL dominant mode of inheritance linked to the FBN1 gene on chromosome 15.
