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Direct observation of structure-function relationship in motor proteins

10/4/2015 Siv Schwink

[image:24753 class:fright]The relationship between protein structure and function is essential in determining mechanism, yet most techniques do not provide a direct measurement of this relationship. The Ha and Chemla labs recently developed a combined optical trap-fluorescence microscope that allows for measurements of structure and function simultaneously. In Comstock, M. J. et al., (2015) Science 348(6232):352-4, they applied this approach to the DNA repair helicase UvrD, showing for the first time how two distinct types of unwinding activity are regulated by its stoichiometry, and how two structural states termed ‘open’ and ‘closed’, the function of which have been debated for years, control its directionality of translocation relative to the DNA fork junction. In a companion study (Arslan, S. et al. (2015) Science 348(6232):344-7), the team engineered homologs of UvrD, locking them into each structural state by intermolecular cross-linking. Locking into the closed conformation turns the proteins into “superhelicases” capable of unwinding DNA over a great distance and against large forces. These findings point to mechanisms by which conformational states control activity and by which these states are regulated in the cell to promote certain functions. Moreover, the ability to bioengineer molecules to perform specific tasks holds promise for applications such as rapid DNA sequencing.


1/21/2014 Lance Cooper

February 3 is the last day for the following:

By Feb. 3 (10th day of classes), graduate students should be correctly registered for spring term. It is important to check your registration before February 3 on Student Web Self Service to make sure that you are registered for the courses that you are attending and attending the courses for which you are registered. If necessary, make any corrections by adding and dropping courses before February 3.

In addition, February 3 is the last day for the following:

-- Drop courses to reduce your number of credit hours you are registered for to a lower tuition range and receive a refund for the difference between the two ranges

-- Add a semester course without permission

-- Submit forms to audit a semester course

-- Add a first half-session course

Students should be registered appropriately no later than February 3 in order to avoid possible issues with

-- Tuition/Fee Assessment
-- Financial aid
-- Loan deferment
-- Health Insurance
-- Academic Record/Graduation issues