Comparative Analysis of TM and Cytoplasmic β-barrel Conformations Using Joint Descriptor

Area of Science:

• Protein structure analysis
• Structural bioinformatics
• Biophysics

Background:

• Macroscopic protein descriptors offer coarse-grained features complementary to microscopic ones.
• Geometric features of proteins are crucial for structural comparison, aiding similarity and dissimilarity searches.
• Beta-barrels are a significant class of protein folds found in both transmembrane and cytoplasmic proteins.

Purpose of the Study:

• To systematically compare the conformational features of transmembrane (TM) beta-barrels and cytoplasmic barrels.
• To evaluate the utility of a novel joint-based descriptor for protein structure comparison.
• To identify differences in geometric arrangements and propensities between TM and cytoplasmic beta-barrels.

Main Methods:

• Utilized a joint-based descriptor incorporating joint coordinates and dihedral angles (β and γ).
• Analyzed β-strand joints and loops to determine local and global arrangements and propensities.
• Performed a systematic comparison of beta-barrel protein structures.

Main Results:

• Confirmed distinct preferences in β and γ distribution between TM and cytoplasmic beta-barrels.
• Identified signature patterns and differences in the number of strand effects.
• Demonstrated clear distinctions in the arrangement of β-strands and loops.

Conclusions:

• The joint-based descriptor provides a reliable method for static structural comparison at the macroscopic level.
• The findings highlight significant geometric differences between transmembrane and cytoplasmic beta-barrels.
• This approach offers a robust and simple tool for analyzing complex protein conformations.