Question

What role do low-barrier hydrogen bonds play in serine protease catalysis?

Short answer

Low-barrier hydrogen bonds contribute to the transition state's stability and help catalyze the reaction.

Step-by-step solution

Low-barrier hydrogen bonds (LBHB)

When the pKa of two heteroatoms are extremely similar, LBHBs, which are particular sorts of hydrogen bonds, are produced. This enables them to share hydrogen atoms equally. As a result, special brief and strong bonds known as LBHB are formed.

Role of LBHB in serine protease catalysis

LBHB stabilizes the transition state during serine protease catalysis. Here, the enzyme's non-aqueous active site contains LBHB. The protonated His and Asp in the serine protease catalytic triad have almost comparable pK values, which results in the creation of LBHB, which further aids in catalyzing the reaction.

Hence, LBHB helps the serine protease catalyzed transition state remains stable.