Molecular Dynamics Simulation of the Bio-Adhesion in Molecular Motors

Molecular dynamics (MD) simulation is employed to study the bio-adhesion in F1 ATP molecular motor. Histidine-peptide is widely used as linkage in micro systems because of its strong binding strength to metals. This paper focuses on the adhesion between a synthetic peptide containing 6xHis-tag (Gly-Gly-Lys-Gly-Gly-Lys-Gly-Gly-His-His-His-His-His-His) and metal substrate, which is used to define the position of the F1 ATP molecular motor on the metal substrate. It is shown that the binding strength between histidine and nickel substrate is the strongest, while that of copper is smaller and that of gold substrate is the smallest. From the result of simulation, we find that the stability of adhesion between histidine and the metal substate result of the ringed structure in histidine.

Perspectives on the origin of microfilaments, microtubules, the relevant chaperonin system and cytoskeletal motors - a commentary on the spirochaete origin of flagella

The origin of cytoskeleton and the origin of relevant intracellular transportation system are big problems for understanding the emergence of eukaryotic cells. The present article summarized relevant information of evidences and molecular traces on the origin of actin, tubulin, the chaperonin system for folding them, myosins, kinesins, axonemal dyneins and cytoplasmic dyneins. On this basis the authors proposed a series of works, which should be done in the future, and indicated the ways for reaching the targets. These targets are mainly: 1) the reconstruction of evolutionary path from MreB protein of archaeal ancestor of eukaryotic cells to typical actin; 2) the finding of the MreB or MreB-related proteins in crenarchaea and using them to examine J. A. Lake's hypothesis on the origin of eukaryote from "eocytes" (crenarchaea); 3) the examinations of the existence and distribution of cytoskeleton made of MreB-related protein within coccoid archaea, especially in amoeboid archaeon Thermoplasm acidophilum; 4) using Thermoplasma as a model of archaeal ancestor of eukaryotic cells; 5) the searching for the homolog of ancestral dynein in present-day living archaea. During the writing of this article, Margulis' famous spirochaete hypothesis on the origin of flagella and cilia was unexpectedly involved and analyzed from aspects of tubulins, dyneins and spirochaetes. Actually, spirochaete cannot be reasonably assumed as the ectosymbiotic ancestor of eukaryotic flagella and cilia, since their swing depends upon large amount of bacterial flagella beneath the flexible outer wall, but not depends upon their intracellular tubules and the assumed dyneins. In this case, if they had "evolved" into cilia and lost their bacterial flagella, they would immediately become immobile! In fact, tubulin and dynein-like proteins have not been found in any spirochaete.