Study of Structural Similarities between Tubulin, TMC1, and FtsZ Proteins as They Relate to Mechanosensory Transduction in the Context of the Orch OR Theory of Consciousness

Abstract

Recent evidence obtained in murine atrial cardiomyocytes suggests that the behavior of tubulin, a constituent of microtubules, is influenced by audible sounds. In the present study, the sequence and the structure of murine and human tubulins were compared with those of human TMC1 (Transmembrane channel-like protein 1), a sound-sensitive protein that is responsible for forming the pore of mechanosensory transduction channels in the hair cells of the inner ear of vertebrates, and with those of bacterial FtsZ (Filamenting temperature-sensitive mutant Z), a bacterial protein homologous to tubulin. The results show that mouse and human alpha-tubulin are 100% identical, whereas sequence homology of human TMC1 and human tubulin alpha 1A chain is scarce, with only 17.31% identity. A higher degree of similarity was observed in the presence of aromatic amino acids as well as in the propensity to form alpha-helices. Based on these results, it is hypothesized that the response of tubulin to audible sounds is mediated by the external alpha-helices as it occurs in TMC1. The sequence homology of human TMC1 and FtsZ from Lactobacillus johnsonii, is moderate with 23.40% identity, however higher than that between TMC1 and tubulin. The overall presence of aromatic amino acids in FtsZ is scarce, but helix propensity is significant. These results are discussed in the context of Orch OR, a theory that postulates that consciousness emerges from quantum computations occurring in microtubules of neurons via information processing mediated by aromatic amino acids of tubulin.