Flap endonucleases (FENs) are proposed to select their target phosphate diester by unpairing the two terminal nucleotides of duplex. Interstrand disulfide crosslinks, introduced by oxidation of thiouracil and thioguanine bases, abolished the specificity of human FEN1 for hydrolysis one nucleotide into the 5'-duplex.

A novel multiple shape memory hydrogel is fabricated based on two reversible physical interactions. The multiple shape memory property is endowed by a simple treatment of soaking in NaOH or NaCl solutions to form chitosan microcrystal or chain-entanglement crosslinks as temporary junctions.

It has long been recognized that the high tensile strength of collagen is due to formation of intermolecular cross-links within the fiber. Following identification of the first of these intermolecular divalent cross-links in 1968 (Bailey and Peach, 1968), several other divalent and multivalent crosslinks have been proposed. Some of these proposed crosslinks have not stood the test of time, subs...

Many natural macromolecules, like proteins and DNA, are equipped with site-specific, non-covalent molecular interactions. These interactions lead to intricate secondary structures such as the double helix, self-assembled phospholipid membrane bilayers, and precisely folded protein structures that are vital to life and rely on non-covalent interactions to “guide” molecular organization. Mankind ...

Attaching a self-complementary zwitterionic supramolecular binding site to the amino groups of polyethyleneimine leads to a pH switchable hydrogel as dimerization of the zwitterions introduces additional crosslinks between the polymer chains. This gel responds to both the addition of either acid or base, as only the zwitterion can self-assemble but neither the protonated or deprotonated form.

Non-enzymatic glycation of extracellular matrix with (U-13C5)-d-ribose-5-phosphate (R5P), enables in situ 2D ssNMR identification of many deleterious protein modifications and crosslinks, including previously unreported oxalamido and hemiaminal (CH3-CH(OH)NHR) substructures. Changes in charged residue proportions and distribution may be as important as crosslinking in provoking and understandin...

Microtubules assemble into arrays of bundled filaments that are critical for multiple steps in cell division, including anaphase and cytokinesis. Recent structural and functional studies, including two papers in this issue of Cell (Bieling et al., 2010; Subramanian et al., 2010), demonstrate how the MAP65 protein PRC1 crosslinks microtubules and cooperates with kinesin motors to control the dyn...