Secondary Structure Prediction for the Spectrin 106-Amino Acid Segment, and a Proposed Model for Tertiary Structure

Abstract
A collective secondary structure prediction for the human erythrocyte spectrin 106-residue repeat segment is developed, based on the sequences of nine segments that have been reported in the literature, utilizing a consensus of several secondary structure prediction methods for locating turn regions. The analysis predicts a five-fold structure, with three α-helices and two β-strand regions, and differs from previous models on the lengths of the helices and the existence of β-strand structure. We also demonstrate that this structural motif can be folded into tertiary structures that satisfy the experimental spectrin data and several general principles of protein organization.