Editing Machine (section)

== Molecular machines ==
[[File:Protein translation.gif|thumb|A [[ribosome]] is a [[biological machine]] that utilizes [[protein dynamics]].]]
The biological molecule [[myosin]] reacts to ATP and ADP to alternately engage with an actin filament and change its shape in a way that exerts a force, and then disengage to reset its shape, or conformation. This acts as the molecular drive that causes muscle contraction. Similarly the biological molecule [[kinesin]] has two sections that alternately engage and disengage with microtubules causing the molecule to move along the microtubule and transport vesicles within the cell, and [[dynein]], which moves cargo inside cells towards the nucleus and produces the axonemal beating of [[cilia#Motile cilia|motile cilia]] and [[flagella]]. "In effect, the motile cilium is a nanomachine composed of perhaps over 600 proteins in molecular complexes, many of which also function independently as nanomachines. [[Flexible linker]]s allow the [[Protein domain#Domains and protein flexibility|mobile protein domains]] connected by them to recruit their binding partners and induce long-range [[allostery]] via [[Protein dynamics#Global flexibility: multiple domains|protein domain dynamics]]. "<ref name="Satir2008">{{cite journal
  | last = Satir
  | first = Peter
  |author2=Søren T. Christensen
  | title = Structure and function of mammalian cilia
  | journal = Histochemistry and Cell Biology
  | volume = 129
  | issue = 6
  | pages = 687–93
  | date = 2008-03-26
  | doi = 10.1007/s00418-008-0416-9
  | id = 1432-119X 
  | pmid = 18365235
  | pmc = 2386530 }}</ref> Other biological machines are responsible for energy production, for example [[ATP synthase]] which harnesses energy from [[Proton-motive force|proton gradients across membranes]] to drive a turbine-like motion used to synthesise [[Adenosine triphosphate|ATP]], the energy currency of a cell.<ref>{{Cite journal|last1=Kinbara|first1=Kazushi|last2=Aida|first2=Takuzo|date=2005-04-01|title=Toward Intelligent Molecular Machines: Directed Motions of Biological and Artificial Molecules and Assemblies|journal=Chemical Reviews|volume=105|issue=4|pages=1377–1400|doi=10.1021/cr030071r|pmid=15826015|issn=0009-2665}}</ref> Still other machines are responsible for [[gene expression]], including [[DNA polymerase]]s for replicating [[DNA]],{{citation needed|date=December 2018}} [[RNA polymerase]]s for producing [[Messenger RNA|mRNA]],{{citation needed|date=December 2018}} the [[spliceosome]] for removing [[intron]]s, and the [[ribosome]] for [[Protein synthesis|synthesising proteins]]. These machines and their [[protein dynamics|nanoscale dynamics]] are far more complex than any [[molecular machine]]s that have yet been artificially constructed.<ref name="pmid21570668">{{cite book |vauthors=Bu Z, Callaway DJ |title=Protein Structure and Diseases |chapter=Proteins MOVE! Protein dynamics and long-range allostery in cell signaling |volume=83 |pages=163–221 |year=2011 |pmid=21570668 |doi=10.1016/B978-0-12-381262-9.00005-7|series=Advances in Protein Chemistry and Structural Biology |isbn=9780123812629}}</ref> These molecules are increasingly considered to be [[nanomachines]].{{citation needed|date=December 2018}}

Researchers have used DNA to construct nano-dimensioned [[four-bar linkage]]s.<ref>[http://www.pnas.org/content/112/3/713.abstract Marras, A., Zhou, L., Su, H., and Castro, C.E. Programmable motion of DNA origami mechanisms, Proceedings of the National Academy of Sciences, 2015] {{webarchive|url=https://web.archive.org/web/20170804052839/http://www.pnas.org/content/112/3/713.abstract |date=2017-08-04 }}</ref><ref>[http://mechanicaldesign101.com/2014/10/21/haijun-su-draft-article/ McCarthy, C, DNA Origami Mechanisms and Machines | Mechanical Design 101, 2014] {{webarchive|url=https://web.archive.org/web/20170918021917/http://mechanicaldesign101.com/2014/10/21/haijun-su-draft-article/ |date=2017-09-18 }}
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