4pN [1st study]: 12 to 15pN [2nd study] pN
||Gennerich A, Vale RD. Walking the walk: how kinesin and dynein coordinate their steps. Curr Opin Cell Biol. 2009 Feb21(1):59-67. doi: 10.1016/j.ceb.2008.12.002. p.62 right column bottom paragraphPubMed ID19179063
||[18••] A. Yildiz, M. Tomishige, A. Gennerich, R.D. Vale Intramolecular strain coordinates kinesin stepping behavior along microtubules Cell, 134 (2008), pp. 1030–1041 doi: 10.1016/j.cell.2008.07.018. [42•] C. Hyeon, J.N. Onuchic Internal strain regulates the nucleotide binding site of the kinesin leading head Proc Natl Acad Sci USA, 104 (2007), pp. 2175–2180PubMed ID18805095, 17287347
||Primary source [18••] abstract:"Kinesin advances 8 nm along a microtubule per ATP hydrolyzed, but the mechanism responsible for coordinating the enzymatic cycles of kinesin's two identical motor domains remains unresolved. Here, [investigators] have tested whether such coordination is mediated by intramolecular tension generated by the "neck linkers," mechanical elements that span between the motor domains." Primary source [42•] abstract:"Recent experiments suggest that ATP binding to the leading head (L) domain in kinesin is regulated by the rearward strain built on the neck-linker. [Investigators] test this hypothesis by explicitly modeling a Calpha-based kinesin structure whose motor domains are bound on the tubulin binding sites."
||P.62 right column bottom paragraph:"These experiments strongly suggest that tension plays an important role in the coordination of kinesin's head domains and that the dimensions and flexibility of the neck linkers are key to tension sensing. Where does the tension come from and what is its magnitude? The tension may derive simply from the MT [microtubule]-binding by the front head, since this alone would stretch out both neck linkers ( Figure 3b). The magnitude of this tension can be estimated from ‘worm-like chain’ models that treat the neck-linker peptide as an entropic spring, but calculations for the forces required to stretch out the neck linkers differ considerably (between 4 pN [primary source 18••] and 12–15 pN [primary source 42•]). The tension also might be enhanced by the initiation of neck-linker docking in the front head (the ATP-driven conformation change) [primary source 18••]."