Rhodopsin activation: Effects of the metarhodopsin I-metarhodopsin II equilibrium of neutralization or introduction of charged amino acids within putative transmembrane segments

Biochemistry ◽  
1993 ◽  
Vol 32 (51) ◽  
pp. 14176-14182 ◽  
Author(s):  
Charles J. Weitz ◽  
Jeremy Nathans
Keyword(s):  
Amino Acids ◽  
Transmembrane Segments ◽  
Charged Amino Acids

scholarly journals Energetics of side-chain snorkeling in transmembrane helices probed by nonproteinogenic amino acids

2016 ◽  
Vol 113 (38) ◽  
pp. 10559-10564 ◽  
Author(s):  
Karin Öjemalm ◽  
Takashi Higuchi ◽  
Patricia Lara ◽  
Erik Lindahl ◽  
Hiroaki Suga ◽  
...  
Keyword(s):  
Amino Acids ◽  
Membrane Protein ◽  
Side Chain ◽  
Transmembrane Helices ◽  
Transmembrane Segments ◽  
Charged Amino Acids ◽  
Protein Biogenesis ◽  
Quantitative Basis ◽  
Apparent Free Energy ◽  
Integration Efficiency

Cotranslational translocon-mediated insertion of membrane proteins into the endoplasmic reticulum is a key process in membrane protein biogenesis. Although the mechanism is understood in outline, quantitative data on the energetics of the process is scarce. Here, we have measured the effect on membrane integration efficiency of nonproteinogenic analogs of the positively charged amino acids arginine and lysine incorporated into model transmembrane segments. We provide estimates of the influence on the apparent free energy of membrane integration (ΔGapp) of “snorkeling” of charged amino acids toward the lipid–water interface, and of charge neutralization. We further determine the effect of fluorine atoms and backbone hydrogen bonds (H-bonds) on ΔGapp. These results help establish a quantitative basis for our understanding of membrane protein assembly in eukaryotic cells.

scholarly journals The Hydrophobic Core of the Sec61 Translocon Defines the Hydrophobicity Threshold for Membrane Integration

2010 ◽  
Vol 21 (10) ◽  
pp. 1662-1670 ◽  
Author(s):  
Tina Junne ◽  
Lucyna Kocik ◽  
Martin Spiess
Keyword(s):  
Amino Acids ◽  
Lipid Bilayer ◽  
Active Role ◽  
Aqueous Environment ◽  
Endoplasmic Reticulum Membrane ◽  
Hydrophobic Core ◽  
Transmembrane Segments ◽  
Constriction Ring ◽  
Charged Amino Acids ◽  
Translocation Efficiency

The Sec61 translocon mediates the translocation of proteins across the endoplasmic reticulum membrane and the lateral integration of transmembrane segments into the lipid bilayer. The structure of the idle translocon is closed by a lumenal plug domain and a hydrophobic constriction ring. To test the function of the apolar constriction, we have mutated all six ring residues of yeast Sec61p to more hydrophilic, bulky, or even charged amino acids (alanines, glycines, serines, tryptophans, lysines, or aspartates). The translocon was found to be surprisingly tolerant even to the charge mutations in the constriction ring, because growth and translocation efficiency were not drastically affected. Most interestingly, ring mutants were found to affect the integration of hydrophobic sequences into the lipid bilayer, indicating that the translocon does not simply catalyze the partitioning of potential transmembrane segments between an aqueous environment and the lipid bilayer but that it also plays an active role in setting the hydrophobicity threshold for membrane integration.

scholarly journals Epitope Mapping of Monoclonal Antibodies to Calreticulin Reveals That Charged Amino Acids Are Essential for Antibody Binding

Antibodies ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 31
Author(s):  
Ann Christina Bergmann ◽  
Cecilie Kyllesbech ◽  
Rimantas Slibinskas ◽  
Evaldas Ciplys ◽  
Peter Højrup ◽  
...  
Keyword(s):  
Amino Acids ◽  
Monoclonal Antibodies ◽  
Epitope Mapping ◽  
Biological Function ◽  
Specific Binding ◽  
Enzyme Linked Immunosorbent Assay ◽  
Potential Therapeutic Target ◽  
Charged Amino Acids ◽  
Chaperone Protein ◽  
Terminal Amino

Calreticulin is a chaperone protein, which is associated with myeloproliferative diseases. In this study, we used resin-bound peptides to characterize two monoclonal antibodies (mAbs) directed to calreticulin, mAb FMC 75 and mAb 16, which both have significantly contributed to understanding the biological function of calreticulin. The antigenicity of the resin-bound peptides was determined by modified enzyme-linked immunosorbent assay. Specific binding was determined to an 8-mer epitope located in the N-terminal (amino acids 34–41) and to a 12-mer peptide located in the C-terminal (amino acids 362–373). Using truncated peptides, the epitopes were identified as TSRWIESK and DEEQRLKEEED for mAb FMC 75 and mAb 16, respectively, where, especially the charged amino acids, were found to have a central role for a stable binding. Further studies indicated that the epitope of mAb FMC 75 is assessable in the oligomeric structure of calreticulin, making this epitope a potential therapeutic target.

scholarly journals The Superagonistic Activity of Bovine Thyroid-stimulating Hormone (TSH) and the Human TR1401 TSH Analog Is Determined by Specific Amino Acids in the Hinge Region of the Human TSH Receptor

2009 ◽  
Vol 284 (24) ◽  
pp. 16317-16324 ◽  
Author(s):  
Sandra Mueller ◽  
Gunnar Kleinau ◽  
Mariusz W. Szkudlinski ◽  
Holger Jaeschke ◽  
Gerd Krause ◽  
...  
Keyword(s):  
Amino Acids ◽  
Thyroid Stimulating Hormone ◽  
Hinge Region ◽  
Camp Production ◽  
Glycoprotein Hormone ◽  
Charged Amino Acids ◽  
Bovine Thyroid ◽  
Positively Charged ◽  
Bovine Tsh ◽  
Signaling Activity

Bovine TSH (bTSH) has a higher affinity to the human TSHR (hTSHR) and a higher signaling activity than human TSH (hTSH). The molecular reasons for these phenomena are unknown. Distinct negatively charged residues (Glu297, Glu303, and Asp382) in the hinge region of the hTSHR are known to be important for bTSH binding and signaling. To investigate the potential relevance of these positions for differences between bTSH and hTSH in the interaction to the hTSHR, we determined bTSH- and hTSH-mediated cAMP production of several substitutions at these three hinge residues. To examine specific variations of hTSH, we also investigated the superagonistic hTSH analog TR1401 (TR1401), whose sequence differs from hTSH by four additional positively charged amino acids that are also present in bTSH. To characterize possible interactions between the acidic hTSHR positions Glu297, Glu303, or Asp382 and the additional basic residues of TR1401, we investigated TR1401 binding and signaling properties. Our data reveal increased cAMP signaling of the hTSHR using TR1401 and bTSH compared with hTSH. Whereas Asp382 seems to be important for bTSH- and TR1401-mediated but not for hTSH-mediated signaling, the substitution E297K exhibits a decreased signaling for all three TSH variants. Interestingly, bTSH and TR1401 showed only a slightly different binding pattern. These observations imply that specific residues of the hinge region are mediators of the superagonistic activity of bTSH and TR1401 in contrast to hTSH. Moreover, the simultaneous localization of binding components in the glycoprotein hormone molecule and the receptor hinge region permits important reevaluation of interacting hormone receptor domains.

scholarly journals Structural basis of adhesive binding by desmocollins and desmogleins

2016 ◽  
Vol 113 (26) ◽  
pp. 7160-7165 ◽  
Author(s):  
Oliver J. Harrison ◽  
Julia Brasch ◽  
Gorka Lasso ◽  
Phinikoula S. Katsamba ◽  
Goran Ahlsen ◽  
...  
Keyword(s):  
Amino Acids ◽  
Crystal Structures ◽  
Structural Basis ◽  
Cellular Interactions ◽  
Opposite Charge ◽  
Charged Amino Acids ◽  
Structural Framework ◽  
Classical Cadherins ◽  
Coated Bead

Desmosomes are intercellular adhesive junctions that impart strength to vertebrate tissues. Their dense, ordered intercellular attachments are formed by desmogleins (Dsgs) and desmocollins (Dscs), but the nature of trans-cellular interactions between these specialized cadherins is unclear. Here, using solution biophysics and coated-bead aggregation experiments, we demonstrate family-wise heterophilic specificity: All Dsgs form adhesive dimers with all Dscs, with affinities characteristic of each Dsg:Dsc pair. Crystal structures of ectodomains from Dsg2 and Dsg3 and from Dsc1 and Dsc2 show binding through a strand-swap mechanism similar to that of homophilic classical cadherins. However, conserved charged amino acids inhibit Dsg:Dsg and Dsc:Dsc interactions by same-charge repulsion and promote heterophilic Dsg:Dsc interactions through opposite-charge attraction. These findings show that Dsg:Dsc heterodimers represent the fundamental adhesive unit of desmosomes and provide a structural framework for understanding desmosome assembly.

Negatively-charged amino acids at the peptide-binding pocket of HLA-DPB1 alleles are associated with susceptibility to anti-topoisomerase I-positive systemic sclerosis

2016 ◽  
Vol 77 (7) ◽  
pp. 550-554 ◽  
Author(s):  
Jeong Seok Lee ◽  
Jin Kyun Park ◽  
Heung Jae Kim ◽  
Hyung Ki Lee ◽  
Yeong Wook Song ◽  
...  
Keyword(s):  
Amino Acids ◽  
Systemic Sclerosis ◽  
Topoisomerase I ◽  
Peptide Binding ◽  
Binding Pocket ◽  
Charged Amino Acids

scholarly journals Interaction of wild-type signal sequences and their charged variants with model and natural membranes

1993 ◽  
Vol 293 (1) ◽  
pp. 43-49 ◽  
Author(s):  
N M Rao ◽  
R Nagaraj
Keyword(s):  
Amino Acids ◽  
Synthetic Peptides ◽  
Model Membranes ◽  
Signal Peptides ◽  
Wild Type ◽  
Signal Sequences ◽  
Hydrophobic Region ◽  
Phospholipases A2 ◽  
Charged Amino Acids

The interaction of synthetic peptides corresponding to wild-type signal sequences, and their mutants having charged amino acids in the hydrophobic region, with model and natural membranes has been studied. At high peptide concentrations, i.e. low lipid/peptide ratios, the signal peptides cause release of carboxyfluorescein (CF) from model membranes with lipid compositions corresponding to those of translocation-competent as well as translocation-incompetent membranes. Interestingly, mutant sequences, which were non-functional in vivo, caused considerable release of CF compared with the wild-type sequences. Both wild-type and mutant signal sequences perturb model membranes even at lipid/peptide ratios of 1000:1, as indicated by the activities of phospholipases A2, C and D. These studies indicate that such mutant signals are non-functional not because of their inability to interact with membranes, but due to defective targeting to the membrane. The signal peptides inhibit phospholipase C activity in microsomes, uncouple oxidative phosphorylation in mitochondria and increase K+ efflux from erythrocytes, and one of the mutant sequences is a potent degranulator of the mast cells. Both wild-type and mutant signal sequences have the ability to perturb vesicles of various lipid compositions. With respect to natural membranes, the peptides do not show any bias towards translocation-competent membranes.

scholarly journals Electron Transfer in Peptides: The Influence of Charged Amino Acids

2011 ◽  
Vol 50 (8) ◽  
pp. 1926-1930 ◽  
Author(s):  
Jian Gao ◽  
Pavel Müller ◽  
Min Wang ◽  
Sonja Eckhardt ◽  
Miriam Lauz ◽  
...  
Keyword(s):  
Amino Acids ◽  
Electron Transfer ◽  
Charged Amino Acids
Sign in / Sign up

Export Citation Format

Share Document