Proteoglycans and collagen molecules are interacting with each other thereby forming various connective tissues. The sulfation pattern of proteoglycans differs depending on the kind of tissue and/or the degree of matu...Proteoglycans and collagen molecules are interacting with each other thereby forming various connective tissues. The sulfation pattern of proteoglycans differs depending on the kind of tissue and/or the degree of maturation. Tissues from Cnidaria are suitable examples for exploration of the effects in relation to the presence and the absence of sulfate groups, when studying characteristic fragments of the long proteoglycan carbohydrate chains in silico. It has been described that a non-sulfated chondroitin appears as a scaffold in early morphogenesis of all nematocyst types in Hydra. On the other hand, sulfated glucosaminoglycans play an important role in various developmental processes of Cnidaria. In order to understand this biological phenomenon on a sub-molecular level we have analysed the structures of sulfated and non-sulfated proteoglycan carbohydrate chains as well as the structure of diverse collagen molecules with computational methods including quantum chemical calculations. The strong interactions between the sulfate groups of the carbohydrates moieties in proteoglycans and positively charged regions of collagen are essential in stabilizing various Cnidaria tissues but could hinder the nematocyst formation and its proper function. The results of our quantum chemical calculations show that the sulfation pattern has a significant effect on the conformation of chondroitin structures under study.展开更多
We here present a detailed study of the ligand-receptor interactions between single and triple-helical strands of collagen and the α2A domain of integrin(α2A),providing valuable new insights into the mechanisms and ...We here present a detailed study of the ligand-receptor interactions between single and triple-helical strands of collagen and the α2A domain of integrin(α2A),providing valuable new insights into the mechanisms and dynamics of collagen-integrin binding at a sub-molecular level.The occurrence of single and triple-helical strands of the collagen fragments was scrutinized with atom force microscopy(AFM)techniques.Strong interactions of the triple-stranded fragments comparable to those of collagen can only be detected for the 42mer triple-helical collagen-like peptide under study(which contains 42 amino acid residues per strand)by solid phase assays as well as by surface plasmon resonance(SPR)measurements.However,changes in NMR signals during titration and characteristic saturation transfer difference(STD)NMR signals are also detectable whenα2A is added to a solution of the 21mer single-stranded collagen fragment.Molecular dynamics(MD)simulations employing different sets of force field parameters were applied to study the interaction between triple-helical or single-stranded collagen fragments withα2A.It is remarkable that even single-stranded collagen fragments can form various complexes withα2A showing significant differences in the complex stability with identical ligands.The results of MD simulations are in agreement with the signal alterations in our NMR experiments,which are indicative of the formation of weak complexes between single-stranded collagen andα2A in solution.These results provide useful information concerning possible interactions ofα2A with small collagen fragments that are of relevance to the design of novel therapeutic A-domain inhibitors.展开更多
基金Elements of the project are financed by the European Commission’s Framework Program 7(BIO-NMR-00007)-Bio-NMR grant:Jellyfish protein NMR(BIO-NMR-00007)-IEP.
文摘Proteoglycans and collagen molecules are interacting with each other thereby forming various connective tissues. The sulfation pattern of proteoglycans differs depending on the kind of tissue and/or the degree of maturation. Tissues from Cnidaria are suitable examples for exploration of the effects in relation to the presence and the absence of sulfate groups, when studying characteristic fragments of the long proteoglycan carbohydrate chains in silico. It has been described that a non-sulfated chondroitin appears as a scaffold in early morphogenesis of all nematocyst types in Hydra. On the other hand, sulfated glucosaminoglycans play an important role in various developmental processes of Cnidaria. In order to understand this biological phenomenon on a sub-molecular level we have analysed the structures of sulfated and non-sulfated proteoglycan carbohydrate chains as well as the structure of diverse collagen molecules with computational methods including quantum chemical calculations. The strong interactions between the sulfate groups of the carbohydrates moieties in proteoglycans and positively charged regions of collagen are essential in stabilizing various Cnidaria tissues but could hinder the nematocyst formation and its proper function. The results of our quantum chemical calculations show that the sulfation pattern has a significant effect on the conformation of chondroitin structures under study.
文摘We here present a detailed study of the ligand-receptor interactions between single and triple-helical strands of collagen and the α2A domain of integrin(α2A),providing valuable new insights into the mechanisms and dynamics of collagen-integrin binding at a sub-molecular level.The occurrence of single and triple-helical strands of the collagen fragments was scrutinized with atom force microscopy(AFM)techniques.Strong interactions of the triple-stranded fragments comparable to those of collagen can only be detected for the 42mer triple-helical collagen-like peptide under study(which contains 42 amino acid residues per strand)by solid phase assays as well as by surface plasmon resonance(SPR)measurements.However,changes in NMR signals during titration and characteristic saturation transfer difference(STD)NMR signals are also detectable whenα2A is added to a solution of the 21mer single-stranded collagen fragment.Molecular dynamics(MD)simulations employing different sets of force field parameters were applied to study the interaction between triple-helical or single-stranded collagen fragments withα2A.It is remarkable that even single-stranded collagen fragments can form various complexes withα2A showing significant differences in the complex stability with identical ligands.The results of MD simulations are in agreement with the signal alterations in our NMR experiments,which are indicative of the formation of weak complexes between single-stranded collagen andα2A in solution.These results provide useful information concerning possible interactions ofα2A with small collagen fragments that are of relevance to the design of novel therapeutic A-domain inhibitors.
