Chloroplasts and bacterial cells divide by binary fission. The key protein in this constriction division is FtsZ, a self-assembling GTPase similar to eukaryotic tubulin. In prokaryotes, FtsZ is almost always encoded b...Chloroplasts and bacterial cells divide by binary fission. The key protein in this constriction division is FtsZ, a self-assembling GTPase similar to eukaryotic tubulin. In prokaryotes, FtsZ is almost always encoded by a single gene, whereas plants harbor several nuclear-encoded FtsZ homologs. In seed plants, these proteins group in two families and all are exclusively imported into plastids. In contrast, the basal land plant Physcomitrella patens, a moss, encodes a third FtsZ family with one member. This protein is dually targeted to the plastids and to the cytosol. Here, we report on the targeted gene disruption of all ftsZ genes in R patens. Subsequent analysis of single and double knockout mutants revealed a complex interaction of the different FtsZ isoforms not only in plastid division, but also in chloroplast shaping, cell patterning, plant development, and gravity sensing. These results support the concept of a plastoskeleton and its functional integration into the cytoskeleton, at least in the moss R patens.展开更多
In the rapidly expanding field of peptide therapeutics,the short in vivo half-life of peptides represents a considerable limitation for drug action.D-peptides,consisting entirely of the dextrorotatory enantiomers of n...In the rapidly expanding field of peptide therapeutics,the short in vivo half-life of peptides represents a considerable limitation for drug action.D-peptides,consisting entirely of the dextrorotatory enantiomers of naturally occurring levorotatory amino acids(AAs),do not suffer from these shortcomings as they are intrinsically resistant to proteolytic degradation,resulting in a favourable pharmacokinetic profile.To experimentally identify D-peptide binders to interesting therapeutic targets,so-called mirror-image phage display is typically performed,whereby the target is synthesized in D-form and L-peptide binders are screened as in conventional phage display.This technique is extremely powerful,but it requires the synthesis of the target in D-form,which is challenging for large proteins.Here we present finDr,a novel web server for the computational identification and optimization of D-peptide ligands to any protein structure(https://findr.biologie.uni-freiburg.de/).finDr performs molecular docking to virtually screen a library of helical 12-mer peptides extracted from the RCSB Protein Data Bank(PDB)for their ability to bind to the target.In a separate,heuristic approach to search the chemical space of 12-mer peptides,finDr executes a customizable evolutionary algorithm(EA)for the de novo identification or optimization of D-peptide ligands.As a proof of principle,we demonstrate the validity of our approach to predict optimal binders to the pharmacologically relevant target phenol soluble modulin alpha 3(PSMα3),a toxin of methicillin-resistant Staphylococcus aureus(MRSA).We validate the predictions using in vitro binding assays,supporting the success of this approach.Compared to conventional methods,finDr provides a low cost and easy-to-use alternative for the identification of D-peptide ligands against protein targets of choice without size limitation.We believe finDr will facilitate D-peptide discovery with implications in biotechnology and biomedicine.展开更多
文摘Chloroplasts and bacterial cells divide by binary fission. The key protein in this constriction division is FtsZ, a self-assembling GTPase similar to eukaryotic tubulin. In prokaryotes, FtsZ is almost always encoded by a single gene, whereas plants harbor several nuclear-encoded FtsZ homologs. In seed plants, these proteins group in two families and all are exclusively imported into plastids. In contrast, the basal land plant Physcomitrella patens, a moss, encodes a third FtsZ family with one member. This protein is dually targeted to the plastids and to the cytosol. Here, we report on the targeted gene disruption of all ftsZ genes in R patens. Subsequent analysis of single and double knockout mutants revealed a complex interaction of the different FtsZ isoforms not only in plastid division, but also in chloroplast shaping, cell patterning, plant development, and gravity sensing. These results support the concept of a plastoskeleton and its functional integration into the cytoskeleton, at least in the moss R patens.
文摘In the rapidly expanding field of peptide therapeutics,the short in vivo half-life of peptides represents a considerable limitation for drug action.D-peptides,consisting entirely of the dextrorotatory enantiomers of naturally occurring levorotatory amino acids(AAs),do not suffer from these shortcomings as they are intrinsically resistant to proteolytic degradation,resulting in a favourable pharmacokinetic profile.To experimentally identify D-peptide binders to interesting therapeutic targets,so-called mirror-image phage display is typically performed,whereby the target is synthesized in D-form and L-peptide binders are screened as in conventional phage display.This technique is extremely powerful,but it requires the synthesis of the target in D-form,which is challenging for large proteins.Here we present finDr,a novel web server for the computational identification and optimization of D-peptide ligands to any protein structure(https://findr.biologie.uni-freiburg.de/).finDr performs molecular docking to virtually screen a library of helical 12-mer peptides extracted from the RCSB Protein Data Bank(PDB)for their ability to bind to the target.In a separate,heuristic approach to search the chemical space of 12-mer peptides,finDr executes a customizable evolutionary algorithm(EA)for the de novo identification or optimization of D-peptide ligands.As a proof of principle,we demonstrate the validity of our approach to predict optimal binders to the pharmacologically relevant target phenol soluble modulin alpha 3(PSMα3),a toxin of methicillin-resistant Staphylococcus aureus(MRSA).We validate the predictions using in vitro binding assays,supporting the success of this approach.Compared to conventional methods,finDr provides a low cost and easy-to-use alternative for the identification of D-peptide ligands against protein targets of choice without size limitation.We believe finDr will facilitate D-peptide discovery with implications in biotechnology and biomedicine.
