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Questions and Answers
Which organelle is involved in the synthesis of the pre-pro α chain?
Which organelle is involved in the synthesis of the pre-pro α chain?
What happens to the signal sequence during the synthesis of the pre-pro α chain?
What happens to the signal sequence during the synthesis of the pre-pro α chain?
What is the role of collagen in the extracellular matrix?
What is the role of collagen in the extracellular matrix?
Which enzyme is responsible for the formation of cross-links in extracellular matrix proteins?
Which enzyme is responsible for the formation of cross-links in extracellular matrix proteins?
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What is the role of lysyl oxidase in collagen fibril formation?
What is the role of lysyl oxidase in collagen fibril formation?
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How are adjacent tropocollagen molecules arranged in the fibrillar array?
How are adjacent tropocollagen molecules arranged in the fibrillar array?
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Which enzyme is responsible for the formation of cross-links in collagen fibrils?
Which enzyme is responsible for the formation of cross-links in collagen fibrils?
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How are adjacent tropocollagen molecules arranged in the fibrillar array?
How are adjacent tropocollagen molecules arranged in the fibrillar array?
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What is the role of lysyl oxidase in collagen fibril formation?
What is the role of lysyl oxidase in collagen fibril formation?
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Which type of array do individual tropocollagen molecules form?
Which type of array do individual tropocollagen molecules form?
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What is the role of lysyl oxidase in collagen fibril formation?
What is the role of lysyl oxidase in collagen fibril formation?
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What is the function of allysine in collagen fibrils?
What is the function of allysine in collagen fibrils?
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Study Notes
Synthesis of Pre-pro α Chain
- The rough endoplasmic reticulum (RER) is the organelle responsible for synthesizing the pre-pro α chain of collagen.
- During synthesis, the signal sequence is initially present at the N-terminus of the pre-pro α chain and is cleaved off to form pro α chain after entering the RER lumen.
Role of Collagen in the Extracellular Matrix
- Collagen provides structural support and strength to tissues, playing a critical role in the integrity of the extracellular matrix (ECM).
- It comprises a significant portion of the ECM, contributing to the framework that supports cells and tissues.
Enzymes and Cross-link Formation
- Lysyl oxidase is the enzyme that facilitates the formation of cross-links between collagen molecules, enhancing the stability and strength of collagen fibrils.
- Cross-linking occurs primarily through the conversion of lysine and hydroxylysine residues into reactive aldehydes, specifically allysine.
Arrangement of Tropocollagen Molecules
- Adjacent tropocollagen molecules are arranged in a staggered pattern, facilitating optimal cross-link formation and contributing to the tensile strength of collagen fibrils.
- This staggered arrangement creates gaps that allow for intermolecular cross-linking, which is essential for the structural integrity of collagen fibers.
Role of Allysine
- Allysine plays a crucial role in collagen fibril stability by participating in covalent cross-linking between adjacent collagen molecules, enhancing the overall strength and durability of the collagen network.
Summary on Collagen Fibril Formation
- Individual tropocollagen molecules form a fibrillar array which is characterized by a regular pattern that contributes to the mechanical properties of tissues.
- Lysyl oxidase is integral in promoting the maturation and stabilization of collagen fibrils through its cross-linking activity, ensuring proper formation and function of the extracellular matrix.
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Description
Test your knowledge on the synthesis of pre-pro α chain and the essential modifications collagen chains undergo in this quiz. Learn about the steps involved in ribosome-mediated synthesis, the role of the signal sequence, and the modifications that enhance stability.
