Final answer:
Positively charged amino acids such as Arginine (Arg) and Lysine (Lys) are likely to be abundant in bFGF due to their ability to bind with negatively charged GAGs. Additionally, in the context of extracellular matrix production, collagen and proteoglycans are the main proteins synthesized by cells to form the matrix.
Step-by-step explanation:
The student asked which amino acids would be abundant in the protein basic fibroblast growth factor (bFGF) that binds to glycosaminoglycans (GAGs) in the extracellular matrix. Amino acids that are positively charged and can form ionic bonds with the negatively charged GAGs in the extracellular matrix would be expected. Thus, amino acids like Arginine (Arg) and Lysine (Lys) would be abundant in such proteins due to their positive charge, which facilitates binding to the negatively charged GAGs. Additionally, Histidine (His) may also be present due to its ability to be positively charged at physiological pH.
In relation to the production of extracellular matrix, we can expect cells, such as fibroblasts which are the most abundant, to synthesize large amounts of collagen and proteoglycans. Collagen provides structural strength due to its fiber-forming capabilities, while proteoglycans, which consist of a core protein and covalently attached GAGs, fill spaces between the cells and fibrous proteins, contributing to the gel-like nature of the matrix and playing a critical role in the binding of growth factors like bFGF.