Pathogenic mutations in the kinesin-3 motor KIF1A diminish force generation and movement through allosteric mechanisms.

The kinesin-3 motor KIF1A functions in neurons, where its fast and superprocessive motility facilitates long-distance transport, but little is known about its force-generating properties. Using optical tweezers, we demonstrate that KIF1A stalls at an opposing load of ~3 pN but more frequently detaches at lower forces. KIF1A rapidly reattaches to the microtubule to resume motion due to its class-specific K-loop, resulting in a unique clustering of force generation events.

Neck linker docking is critical for Kinesin-1 force generation in cells but at a cost to motor speed and processivity.

Kinesin force generation involves ATP-induced docking of the neck linker (NL) along the motor core. However, the roles of the proposed steps of NL docking, cover-neck bundle (CNB) and asparagine latch (N-latch) formation, during force generation are unclear. Furthermore, the necessity of NL docking for transport of membrane-bound cargo in cells has not been tested.

The Structure and Dynamics of C. elegans Tubulin Reveals the Mechanistic Basis of Microtubule Growth.

The dynamic instability of microtubules is a conserved and fundamental mechanism in eukaryotes. Yet microtubules from different species diverge in their growth rates, lattice structures, and responses to GTP hydrolysis. Therefore, we do not know what limits microtubule growth, what determines microtubule structure, or whether the mechanisms of dynamic instability are universal.

A posttranslational modification of the mitotic kinesin Eg5 that enhances its mechanochemical coupling and alters its mitotic function.

Numerous posttranslational modifications have been described in kinesins, but their consequences on motor mechanics are largely unknown. We investigated one of these-acetylation of lysine 146 in Eg5-by creating an acetylation mimetic lysine to glutamine substitution (K146Q). Lysine 146 is located in the α2 helix of the motor domain, where it makes an ionic bond with aspartate 91 on the neighboring α1 helix.

Altered chemomechanical coupling causes impaired motility of the kinesin-4 motors KIF27 and KIF7.

Kinesin-4 motors play important roles in cell division, microtubule organization, and signaling. Understanding how motors perform their functions requires an understanding of their mechanochemical and motility properties. We demonstrate that KIF27 can influence microtubule dynamics, suggesting a conserved function in microtubule organization across the kinesin-4 family.

Investigating Protein Sequence-structure-dynamics Relationships with Bio3D-web.

We demonstrate the usage of Bio3D-web for the interactive analysis of biomolecular structure data. The Bio3D-web application provides online functionality for: (1) The identification of related protein structure sets to user specified thresholds of similarity; (2) Their multiple alignment and structure superposition; (3) Sequence and structure conservation analysis; (4) Inter-conformer relationship mapping with principal component analysis, and (5) comparison of predicted internal dynamics via ensemble normal mode analysis. This integrated functionality provides a complete online workflow for investigating sequence-structure-dynamic relationships within protein families and superfamilies.

Online interactive analysis of protein structure ensembles with Bio3D-web.

Unlabelled: Bio3D-web is an online application for analyzing the sequence, structure and conformational heterogeneity of protein families. Major functionality is provided for identifying protein structure sets for analysis, their alignment and refined structure superposition, sequence and structure conservation analysis, mapping and clustering of conformations and the quantitative comparison of their predicted structural dynamics.

Availability: Bio3D-web is based on the Bio3D and Shiny R packages.

Adapting a database of text messages to a mobile-based weight loss program: the case of the middle East.

Obesity has become a worldwide epidemic. Qatar, a rapidly developing country in the Middle East, has seen a sharp increase in the prevalence of obesity. The increase can be attributed to several reasons, including sedentary lifestyles imposed by a harsh climate and the introduction of Western fast food.