Blue-light induced interaction of LOV domains from Chlamydomonas reinhardtii.

The phototropin from Chlamydomonas reinhardtii is a 120 kDa blue light receptor that plays a key role in gametogenesis of this green alga. It comprises two light-sensing domains termed LOV1 and LOV2 (light oxygen and voltage) and a serine/threonine kinase domain. The post-translationally incorporated chromophore is flavin mononucleotide (FMN).

Isoenzyme-specific differences in the degradation of hyaluronic acid by mammalian-type hyaluronidases.

Bovine testicular hyaluronidase (BTH) has been used as a spreading factor for many years and was primarily characterized by its enzymatic activity. As recombinant human hyaluronidases are now available the bovine preparations can be replaced by the human enzymes. However, data on the pH-dependent activity of hyaluronidases reported in literature are inconsistent in part or even contradictory.

Kinetics of Hyal-1 and PH-20 hyaluronidases: comparison of minimal substrates and analysis of the transglycosylation reaction.

The availability of recombinant expression systems for the production of purified human hyaluronidases PH-20 and Hyal-1 facilitated the first detailed analysis of the enzymatic reaction products. The human recombinant enzymes, both expressed by Drosophila Schneider-2 (DS-2) cells, were compared to bovine testicular hyaluronidase (BTH), a commercially available hyaluronidase preparation, which has long been considered a prototype of mammalian hyaluronidases. The conversion of low molecular weight hyaluronic acid (HA) fragments was detected by a capillary zone electrophoresis (CZE) method.

Recombinant human hyaluronidase Hyal-1: insect cells versus Escherichia coli as expression system and identification of low molecular weight inhibitors.

The human hyaluronidase Hyal-1, one of six human hyaluronidase subtypes, preferentially degrades hyaluronic acid present in the extracellular matrix of somatic tissues. Modulations of Hyal-1 expression have been observed in a number of malignant tumors. However, its role in disease progression is discussed controversially due to limited information on enzyme properties as well as the lack of specific inhibitors.

Binding, domain orientation, and dynamics of the Lck SH3-SH2 domain pair and comparison with other Src-family kinases.

The catalytic activity of Src-family kinases is regulated by association with its SH3 and SH2 domains. Activation requires displacement of intermolecular contacts by SH3/SH2 binding ligands resulting in dissociation of the SH3 and SH2 domains from the kinase domain. To understand the contribution of the SH3-SH2 domain pair to this regulatory process, the binding of peptides derived from physiologically relevant SH2 and SH3 interaction partners was studied for Lck and its relative Fyn by NMR spectroscopy.

Characterization of Lck-binding elements in the herpesviral regulatory Tip protein.

Herpesvirus saimiri encodes a tyrosine kinase interacting protein (Tip) that binds to T-cell-specific tyrosine kinase Lck via multiple sequence motifs and controls its activity. The regulation of Lck by Tip represents a key mechanism in the transformation of human T-lymphocytes during herpesviral infection. In this study, the interaction of Tip with the regulatory SH3 and SH2 domains of Lck was investigated by biophysical and computational techniques.