TY  - JOUR
A1  - Müller, T.
A1  - Dieckmann, T.
A1  - Sebald, Walter
A1  - Oschkinat, H.
T1  - Aspects of receptor binding and signalling of interleukin-4 investigated by site-directed mutagenesis and NMR spectroscopy
N2  - Cytokines are hormones that carry information from ceJI to ceH. This information is read from their surface upon binding to transmembrane receptors and by the subsequent initiation of receptor oligomerization. An inftuence on this process through mutagenesis on the hormone surface is highly desirab)e for medical reasons. However, an understanding of hormone-receptor interactions requires insight into the structural changes introduced by the mutations. In this line structural studies on human TL-4 and the medically important IL-4 antagonists YI24D and Y124G are presented. The site a.round YI24 is an important epitope responsible for the a.bility of 11-4 t.o ca.use a signal in the target cells. It is shown that the local main-chain structure around residue 124 in the variants remains unchanged. A strategy is presented here which allows the study of these types of proteins and their variants by NMR which does not require carbon Iabeiied sa.mples.
KW  - Biochemie
KW  - Interleukin-4
KW  - protein structure
KW  - NMR
KW  - signal transduction
Y1  - 1994
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-62444
ER  - 
TY  - JOUR
A1  - Müller, T.
A1  - Sebald, Walter
A1  - Oschkinat, H.
T1  - Antagonist design through forced electrostatic mismatch
N2  - No abstract available
KW  - Biochemie
Y1  - 1994
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-62408
ER  - 
TY  - JOUR
A1  - Kruse, N.
A1  - Shen, B. J.
A1  - Arnold, S.
A1  - Tony, H. P.
A1  - Müller, T.
A1  - Sebald, Walter
T1  - Two distinct functional sites of human interleukin 4 are identified by variants impaired in either receptor binding or receptor activation
N2  - Interleukin 4 (IL-4) exerts a decisive role in the coord.ination of proteelive immune responses against parasites, particularly helminths. A disregulation of ll.r4 function is possibly involved in the genesis of allergic disease states. The search for important amino acid residues in human ll.r4 by mutational analysis of charged invariant amino acid positions identified two distinct functional sites in the 4-helix-bundle protein. Site 1 was marked by amino acid substitutions of the glutamic acid at position 9 in helix A and arginine at position 88 in helix C. Exchanges at both positions led to IL-4 variants deficient in binding to the extracellular domain of the ll.r4 receptor (IL-4ReJ. In parallel, up to 1000-fold increased concentrations of this type of variant were required to induce T -cell proliferation and B-eeil CD23 expression. Site 2 was marked by amino acid exchanges in helix D at positions 121, 124 and 125 (arginine, tyrosine and serine respectively in the wild-type).ß.A variants affected at site 2 exhibited partial agonist activity during T -cell proliferation; however, they still bound with high affinity to IL-4Rex. [The generation of an IL-4 antagonist by replacing tyrosine 124 with aspartic acid has been described before by Kruse et al. (1992) (EMBO }., 11, 3237-3244)]. These findings indicate that IL-4 functions by bind.ing IL-4Rex via site 1 which is constituted by residues on helices A and C. They further suggest that the association of a second, still undetined receptor protein with site 2 in helix D activates the receptor system and generates a transmembrane signal.
KW  - Biochemie
KW  - drug design/partial agonists
KW  - receptor signalling
Y1  - 1993
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-62451
ER  -