Which protein is a main constituent of connective tissue?

Collagen is a main constituent of connective tissue due to its role in providing strength and structural integrity. It is the most abundant protein in the human body and is a key component of various tissues, including skin, tendons, ligaments, and cartilage. Collagen fibers form a scaffold that helps maintain the shape and firmness of tissues, enabling them to withstand tension and provide support.

The unique triple-helix structure of collagen allows it to have tensile strength, making it ideal for its primary functions in connective tissues. This is why collagen is crucial for maintaining the flexibility and resilience of tissues while also playing a role in wound healing and tissue repair.

Other proteins mentioned, such as keratin, elastin, and fibronectin, also have important roles in the body but are not the primary constituents of connective tissue. Keratin, for instance, is primarily found in epithelial tissues such as hair and nails, elastin provides elasticity to tissues, and fibronectin is involved in cellular adhesion and signaling rather than serving as a structural component like collagen.