Escherichia coli K1 is responsible for 80% of E. coli neonatal meningitis and is a common pathogen in urinary tract infections. Bacteria of this serotype are encapsulated with the alpha(2-8)-polysialic acid NeuNAc(alpha2-8), common to several bacterial pathogens. The gene cluster encoding the pathway for synthesis of this polymer is organized into three regions: (i) kpsSCUDEF, (ii) neuDBACES, a...

Elucidation of mechanisms and discovery of novel reactions are interconnected, as four research chapters from the Munich laboratory demonstrate. 1) In a new opening of the furan ring, 2-methoxyfuran and tetra-acceptor-substituted ethylenes furnish methyl acrylates, which are cis-3-substituted by a cyclopropyl ring that bears the four acceptor groups. Experiments with trans- and cis-1,2-bis(trif...

Thirteen recombinant alpha A-crystallin mutants were constructed that differed in the type of amino acid residue directly preceding the sole amine donor lysine for transglutaminases in this protein. The capacity of these mutants to be cross-linked to amine acceptor substrates by tissue transglutaminase and factor XIII was assessed. Two different biotinylated glutamine-containing oligopeptides w...

Short peptide substrates with high specificity toward transglutaminase (TGase) enzyme were designed, characterized, and coupled to a biocompatible polymer, allowing for rapid enzymatic cross-linking of peptide-polymer conjugates into hydrogels. Eight acyl acceptor Lys-peptide substrates and three acyl donor Gln-peptide substrates were rationally designed and synthesized. The kinetic constants o...

The plant UDP-dependent glucosyltransferase (UGT) BpUGT94B1 catalyzes the synthesis of a glucuronosylated cyanidin-derived flavonoid in red daisy (Bellis perennis). The functional properties of BpUGT94B1 were investigated using protein modeling, site-directed mutagenesis, and analysis of the substrate specificity of isolated wild-type and mutated forms of BpUGT94B1. A single unique arginine res...

EXTL2, an alpha1,4-N-acetylhexosaminyltransferase, catalyzes the transfer reaction of N-acetylglucosamine and N-acetylgalactosamine from the respective UDP-sugars to the non-reducing end of [glucuronic acid]beta1-3[galactose]beta1-O-naphthalenemethanol, an acceptor substrate analog of the natural common linker of various glycosylaminoglycans. We have solved the x-ray crystal structure of the ca...

An effective chiral Lewis acid-catalyzed asymmetric Baylis-Hillman reaction is described. Good to high enantioselectivities were obtained using 3 mol % chiral catalyst. Novel camphor-derived dimerized ligands were prepared from the condensation of (+)-ketopinic acid with the corresponding diamines and hydrazine under acidic conditions. When alpha-naphthyl acrylate was used as a Michael acceptor...

In the title compound, C(11)H(12)N(2)O(3)·H(2)O, the water mol-ecule is a hydrogen-bond donor to the double-bond amide and the carbonyl O atoms of two acid mol-ecules; it is also a hydrogen-bond acceptor to the acid -OH and amide -NH- groups. These hydrogen-bonding inter-actions give rise to a layer structure, with the layers parallel to the ab plane.

Glycosyltransferases are involved in the biosynthesis of protein-bound glycan chains that have multiple and important biological functions in all species. In this protocol, we describe methods to assess the inhibition of glycosyltransferase activities. The kinetic mechanisms of the enzymes, information from structural studies and preliminary inhibition studies can aid in designing appropriate i...

The effects of C by N replacement on the intramolecular hydrogen bond of malonaldehyde have been analyzed through the use of B3LYP/6-311++G(3df,2p)//B3LYP/6-311+G(d,p) calculations. Formylformimidic acid (1) exhibits a IMHB much stronger than that of malonaldehyde, reflecting the enhancement of both the intrinsic acidity and basicity of the HB donor and HB acceptor, when C is replaced by nitrog...