Zukunftsbild Fokussiert – Naturerleben

Zukunftsbilder, Visions of the Future13. Climate action3. Good health and well-being15. Life on lan

Zukunftsbild Fokussiert – Ernährung

Zukunftsbilder, Visions of the Future2. Zero hunger3. Good health and well-being13. Climate actio

The Solution Structure of a Chimeric LEKTI Domain Reveals a Chameleon Sequence

The conversion of an α-helical to a β-strand conformation and the presence of chameleon sequences are fascinating from the perspective that such structural features are implicated in the induction of amyloid-related fatal diseases. In this study, we have determined the solution structure of a chimeric domain (Dom1PI) from the multidomain Kazal-type serine proteinase inhibitor LEKTI using multidimensional NMR spectroscopy. This chimeric protein was constructed to investigate the reasons for differences in the folds of the homologous LEKTI domains 1 and 6 [Lauber, T., et al. (2003) J. Mol. Biol. 328, 205−219]. In Dom1PI, two adjacent phenylalanine residues (F28 and F29) of domain 1 were substituted with proline and isoleucine, respectively, as found in the corresponding P4‘ and P5‘ positions of domain 6. The three-dimensional structure of Dom1PI is significantly different from the structure of domain 1 and closely resembles the structure of domain 6, despite the sequence being identical to that of domain 1 except for the two substituted phenylalanine residues and being only 31% identical to the sequence of domain 6. The mutation converted a short 310-helix into an extended loop conformation and parts of the long COOH-terminal α-helix of domain 1 into a β-hairpin structure. The latter conformational change occurs in a sequence stretch distinct from the region containing the substituted residues. Therefore, this switch from an α-helical structure to a β-hairpin structure indicates a chameleon sequence of seven residues. We conclude that the secondary structure of Dom1PI is determined not only by the local protein sequence but also by nonlocal interactions

LEKTI domain 15 is a functional Kazal-type proteinase inhibitor

The multidomain proteinase inhibitor LEKTI (lympho-epithelial Kazal-type related inhibitor) consists of 15 potential serine proteinase inhibitory domains. In various diseases such as the severe skin disorder Netherton syndrome as well as atopy, defects in the gene encoding LEKTI have been identified that generate premature termination codons of translation, suggesting a specific role of the COOH-terminal part of LEKTI in healthy individuals. We overexpressed and purified a sequence comprising the 15th domain of LEKTI for further characterisation. Here, we present a high yield expression system for recombinant production and efficient purification of LEKTI domain 15 as a highly soluble protein with a uniform disulfide pattern that is identical to that of other known Kazal-type inhibitors. Also, the expected P1P1′ site was confirmed. LEKTI domain 15 is a well-structured protein as verified by circular dichroism (CD) spectroscopy and a tight-binding and stable inhibitor of the serine proteinase trypsin. These findings confirm the designation of domain 15 as a proteinase inhibitor of the Kazal family

Tryptase β regulation of joint lubrication and inflammation via proteoglycan-4 in osteoarthritis

Altered expression and function of the extracellular matrix protein PRG4 have been associated with osteoarthritis. Here, the authors show that mast cell tryptase β cleaves PRG4, resulting in a reduction of lubrication and activation of inflammation in this context