{"id":83142,"date":"2018-09-29T07:53:31","date_gmt":"2018-09-29T14:53:31","guid":{"rendered":"https:\/\/lifeboat.com\/blog\/2018\/09\/molecular-switches-are-not-just-on-or-off"},"modified":"2018-09-29T07:53:31","modified_gmt":"2018-09-29T14:53:31","slug":"molecular-switches-are-not-just-on-or-off","status":"publish","type":"post","link":"https:\/\/lifeboat.com\/blog\/2018\/09\/molecular-switches-are-not-just-on-or-off","title":{"rendered":"Molecular switches are not just \u2018on\u2019 or \u2018off\u2019"},"content":{"rendered":"

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\ud83d\udc40<\/p>\n

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The GTPases constitute a very large protein family, whose members are involved in the control of cell growth, transport of molecules, synthesis of other proteins, etc. Despite the many functions of the GTPases, they follow a common cyclic pattern (Figure 1). The activity of the GTPases is regulated by factors that control their ability to bind and hydrolyse guanosine triphosphate (GTP) to guanosine diphosphate (GDP). So far, it has been the general assumption that a GTPase is active or \u201con\u201d when it is bound to GTP and inactive or \u201coff\u201d in complex with GDP. The GTPases are therefore sometimes referred to as molecular \u201cswitches.\u201d<\/p>\n

The bacterial translational elongation factor EF-Tu is a GTPase, which plays a crucial role during the synthesis of proteins in bacteria, as the factor transports the amino acids that build up a cell\u2019s proteins to the cellular protein synthesis factory, the ribosome. Previous structural studies using X-ray crystallography have shown that EF-Tu occurs in two markedly different three-dimensional shapes depending on whether the factor is \u201con\u201d (i.e. bound to GTP) or \u201coff\u201d (i.e. bound to GDP) (Figure 2). The binding of GTP\/GDP have therefore always been thought to be decisive for the factor\u2019s structural conformation.<\/p>\n

However, a research collaboration between researchers from the Department of Molecular Biology and Genetics at Aarhus University and two American universities reveals that EF-Tu\u2019s structure and function, and probably also those of other GTPases, are far more complex than previously assumed. In S\u00f8ren Thirup\u2019s group, X-ray crystallographic analysis of E. coli EF-Tu has shown that EF-Tu bound to a variant of GTP, GDPNP, can also occur in the \u201coff\u201d state, which is characterised by a more open structure. In collaboration with American researchers, Charlotte Knudsen\u2019s Ph.D. student, Darius Kavaliauskas, conducted further studies using a special form of fluorescence microscopy that makes it possible to observe the spatial structure of individual EF-Tu molecules in solution.<\/p>\n

<\/p>\n","protected":false},"excerpt":{"rendered":"

\ud83d\udc40 The GTPases constitute a very large protein family, whose members are involved in the control of cell growth, transport of molecules, synthesis of other proteins, etc. Despite the many functions of the GTPases, they follow a common cyclic pattern (Figure 1). The activity of the GTPases is regulated by factors that control their ability [\u2026]<\/p>\n","protected":false},"author":501,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[3,412],"tags":[],"class_list":["post-83142","post","type-post","status-publish","format-standard","hentry","category-biological","category-genetics"],"_links":{"self":[{"href":"https:\/\/lifeboat.com\/blog\/wp-json\/wp\/v2\/posts\/83142","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/lifeboat.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/lifeboat.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/lifeboat.com\/blog\/wp-json\/wp\/v2\/users\/501"}],"replies":[{"embeddable":true,"href":"https:\/\/lifeboat.com\/blog\/wp-json\/wp\/v2\/comments?post=83142"}],"version-history":[{"count":0,"href":"https:\/\/lifeboat.com\/blog\/wp-json\/wp\/v2\/posts\/83142\/revisions"}],"wp:attachment":[{"href":"https:\/\/lifeboat.com\/blog\/wp-json\/wp\/v2\/media?parent=83142"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/lifeboat.com\/blog\/wp-json\/wp\/v2\/categories?post=83142"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/lifeboat.com\/blog\/wp-json\/wp\/v2\/tags?post=83142"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}