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Light of specific wavelengths can be used to boost an enzyme's function by as much as 30 fold, potentially establishing a path to less expensive biofuels, detergents and a host of other products. In a paper published in The Journal of Physical Chemistry Letters, a team led by Pratul Agarwal of the Department of Energy's Oak Ridge National Laboratory described a process that aims to improve upon nature - and it happens in the blink of an eye. "When light enters the eye and hits the...

Single amino acid exerts 'remote control' over double bond placement by desaturase enzymes Scientists at the U.S. Department of Energy's (DOE) Brookhaven National Laboratory and collaborators at the Karolinska Institute in Sweden have discovered how an enzyme "knows" where to insert a double bond when desaturating plant fatty acids. Understanding the mechanism — which relies on a single amino acid far from the enzyme's active site — solves a 40-year mystery of how these enzymes exert...

During the evolution of plants of the mustard family a leucine producing enzyme mutated into an enzyme that protects plants against herbivoresPlants are continually exposed to herbivore attack. To defend themselves, they have developed sophisticated chemical defense mechanisms. Plants of the mustard family, such as thale cress (Arabidopsis thaliana), produce glucosinolates (mustard oil glucosides) to protect themselves against herbivory. Scientists know many different kinds of these...

Chemists in Mülheim devise a new way of optimizing enzymes for industrial applicationsEngineers are unlikely to tinker with the cooling system if they want to increase the size of an engine. Yet chemists at the Max Planck Institute for Coal Research have adopted an approach similar to this in their efforts to optimize an enzyme for practical applications. They substituted two amino acids at a site relatively distal to the biocatalyst's binding pocket, the location where the chemical...

Novel therapies could improve potency of existing AIDS treatments, help to combat drug-resistant virus strainsA team of scientists at The Scripps Research Institute has identified two compounds that act on novel binding sites for an enzyme used by the human immunodeficiency virus (HIV), the virus that causes AIDS. The discovery lays the foundation for the development of a new class of anti-HIV drugs to enhance existing therapies, treat drug-resistant strains of the disease, and slow the...

A harmless digestive enzyme evolved twice into a dangerous toxin in 2 unrelated speciesBiologists have shown that independent but similar molecular changes turned a harmless digestive enzyme into a toxin in two unrelated species -- a shrew and a lizard -- giving each a venomous bite.The work, described this week in the journal Current Biology by researchers at Harvard University, suggests that protein adaptation may be a highly predictable process, one that could eventually help discover...

Scientists at Fox Chase Cancer Center have discovered a unique method of attack that may be used to inhibit signaling enzymes called kinases, which often have a role in sustaining drug-resistant cancerous cells. They have confirmed that IPA-3, a small molecular inhibitor of a kinase called PAK1, targets the enzyme's regulatory domain, mimicking how enzymes are naturally regulated within cells."Typically, research has focused on ways of blocking the active site of enzymes, the part of the...

In a landmark technical achievement, investigators in the Vanderbilt Center for Structural Biology have used nuclear magnetic resonance (NMR) methods to determine the structure of the largest membrane-spanning protein to date.Although NMR methods are routinely used to "take molecular pictures" of small proteins, large proteins "“ and particularly those that reside within the cell membrane "“ have been reluctant to smile for the camera.In the June 26 issue of Science, Charles...

By Kubiak, Karina Nowak, Wieslaw ABSTRACT Nitrile hydratase (NHase) is an enzyme used in the industrial biotechnological production of acrylamide. The active site, which contains nonheme iron or noncorrin cobalt, is buried in the protein core at the interface of two domains, alpha and beta. Hydrogen bonds between betaArg-56 and alphaCys-114 sulfenic acid (alphaCEA114) are important to maintain the enzymatic activity. The enzyme may be inactivated by endogenous nitric oxide (NO) and activated...

By Brack, Antje Hellmann, Nadja; Decker, Heinz ABSTRACT Tyrosinases catalyze hydroxylation of monophenols to o- diphenols and their subsequent oxidation to o-quinones, whereas catecholoxidases catalyze only the latter reaction. Both enzymes occur in all organisms and are Type 3 copper proteins that perform the first steps of melanin formation. In arthropods, they play an essential role in the sclerotization of the exoskeleton. Very few phenoloxidases are characterized structurally or...