Biological complexity: intracellular protein movements (Introduction)

by David Turell , Monday, April 03, 2023, 14:59 (390 days ago) @ David Turell

How Kinesin moves along microtubules:

https://www.the-scientist.com/news-opinion/high-resolution-microscope-watches-proteins-...

"Kinesin is a vital player in transporting cargo, like neurotransmitter-filled vesicles, along the microtubule rails that span our cells. Fueled by the splitting of ATP, kinesin moves by “stepping” with its two footlike head groups, which alternate their position along the microtubule.

"The researchers noticed that kinesin walks unevenly along the microtubule, in an alternating pattern of long and short strides, caused by rotation of the protein’s stalk. They also revealed that ATP binds to the protein when just one of its two head groups is planted on the microtubule. Researchers had previously been divided over whether ATP binds in the two-head state—with both head groups firmly planted—or in the one-head state, with one head lifted off the microtubule. But the new work “settles the issue,” says biophysicist Devarajan Thirumalai at the University of Texas at Austin who was not involved in the study.

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"Martin Aepfelbacher, a microbiologist at the University Medical Centre Hamburg-Eppendorf in Germany, has already harnessed the previous iteration of MINFLUX to visualize molecular machines in bacteria. But the new technique could allow his group “to observe the movements of individual proteins in action,” he says, vastly improving the level of detail that can be observed when it comes to biological activity at the nanoscale.

"The illustration explained: KINESIN CATWALK: Researchers tweaked a type of fluorescence microscope capable of detecting individual proteins, known as MINFLUX, to enhance its spatiotemporal resolution. Researchers attached a fluorescence molecule to the motor protein kinesin and tracked it with lasers to observe it walking along a microtubule. The protein was found to meander in alternating long and short steps as its stalk rotated and attached to ATP when just a single head group was bound to the microtubule."

Comment: look at the illustration for full understanding. Kinesin's step-by-step 'walk' is explained. Certainly designed as irreducibly complex in working parts.