The SIP peptide binding pocket is the docking station of the eight amino acid leaderless peptide signal, speB-inducing peptide (SIP). The binding pocket is a tripartite construction of the C-terminals α12 helix which is a capping helix, TPR3s α6 helix that has a hydrophobic interplay with SIP sidechains, and TPR 4's α8 helix which electrostatically stabilizes SIP. Variations in pH level altered strength of adherence between SIP and the SIP binding pocket with acidic pH levels between 5.5 and 6.5 enhancing adherence and pH levels between 7 and 9 reducing adherence.