Avital Klein

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Sialic acids are a family of 9-carbon carboxylated sugars, where different substitutions of the backbone define over 30 members. Biological roles of these substitutions have been missed until recently because of their low abundance and lability to conventional isolation/purification methods. This new approach characterizes sialic acids using electrospray(More)
The structure of sialylated carbohydrate units of bronchial mucins obtained from cystic fibrosis patients was investigated by 500-MHz 1H NMR spectroscopy in conjunction with sugar analysis. After subjecting the mucins to alkaline borohydride degradation, sialylated oligosaccharide-alditols were isolated by anion-exchange chromatography and fractionated by(More)
Carbohydrate chains of respiratory-mucus glycopeptides from a patient (blood group O) suffering from bronchiectasis with a Kartagener's syndrome have been released by alkaline borohydride treatment. Application of high-performance liquid chromatography using subsequently two silica columns, one bonded with aminopropyl groups and the other with octadecyl(More)
A coenzyme-F420 non-reducing [NiFe] hydrogenase was isolated from Methanococcus voltae. It consists of three subunits. They are the products of the previously identified genes vhuA, vhuG and vhuU. The vhuU gene product is of only 25 amino acids. This novel very small hydrogenase subunit contains selenocysteine within a conserved amino-acid sequence(More)
A methylviologen and 8-hydroxy-5-deazaflavin(F420)-reducing hydrogenase was purified over 800-fold to near homogeneity from the archaebacterium Methanococcus voltae with 10 U mg-1 F420-reducing activity. It is the only hydrogenase in this organism. The enzyme showed Km values of 16 microM for F420 and 1.2 mM for methylviologen. A turnover number of 1050(More)
We compared the chemical composition of salivary mucin glycopeptides from cystic fibrosis (CF) and from non-CF subjects and the adhesion of Pseudomonas aeruginosa to these different salivary glycopeptides. Three pools of CF saliva, four pools of non-CF saliva, one individual CF saliva, and one individual non-CF saliva were studied. The soluble fraction of(More)
Sialic acids can be acetylated at the 4, 7, 8 and/or 9 position. Biological roles of these substitutions have been missed until recently because of their low abundance and lability to conventional purification methods. The recent advances in the analysis of sialic acids have allowed to demonstrate that O-acetylation has a selective but widespread(More)
Human respiratory mucins consist of a family of glycoproteins with different peptides in which glycosylation, the major post-translational phenomenon, is responsible for about 70 to 80% of the weight of these molecules. This glycosylation generates a remarkable diversity of O-glycosidically linked carbohydrate chains, which are expressed as several hundreds(More)
[NiFe]-hydrogenases generally carry the bimetallic Ni-Fe reaction center on their largest subunit. The [NiFeSe]-hydrogenase Vhu from Methanococcus voltae has an unusual subunit composition. Some of the amino acids participating in the formation of the reaction center are within a separate, very small subunit, called VhuU. It consists of only 25 amino acids(More)