Accommodating sequence changes in beta-hairpins in proteins

Area of Science:

• Protein structure and bioinformatics
• Molecular biology and biophysics

Background:

• Beta-hairpins are crucial structural motifs in proteins.
• Understanding how sequence variations impact protein structure is vital.

Purpose of the Study:

• To systematically investigate how insertions and deletions (indels) are accommodated in homologous protein beta-hairpins.
• To provide insights for modeling beta-hairpins in related protein structures.

Main Methods:

• Analysis of 49 independent beta-hairpins across 50 protein structures from 12 protein families.
• Classification of hairpins based on loop length and hydrogen bonding patterns.
• Quantification of indel frequency and location within beta-hairpin structures.

Main Results:

• Most indels occur in loops, with frequency decreasing sharply as indel size increases.
• Short loops often feature glycines and readily convert between beta-turn types.
• Longer insertions can be accommodated by extending beta-ladders or forming beta-bulges.

Conclusions:

• Beta-hairpin structure accommodates sequence indels through various mechanisms, predominantly in loops.
• The findings offer a framework for predicting and modeling beta-hairpin conformations in homologous proteins.