scholarly journals Functional role of positively selected amino acid substitutions in mammalian rhodopsin evolution

2016 ◽  
Vol 6 (1) ◽  
Author(s):  
Miguel A. Fernández-Sampedro ◽  
Brandon M. Invergo ◽  
Eva Ramon ◽  
Jaume Bertranpetit ◽  
Pere Garriga
Keyword(s):  
Amino Acid ◽  
Functional Role ◽  
Amino Acid Substitutions

scholarly journals Effects of Amino Acid Substitutions at Conserved and Acidic Residues within Region 1.1 of Escherichia coli ς70

2000 ◽  
Vol 182 (1) ◽  
pp. 221-224 ◽  
Author(s):  
Christina Wilson Bowers ◽  
Andrea McCracken ◽  
Alicia J. Dombroski
Keyword(s):  
Escherichia Coli ◽  
Amino Acid ◽  
Aspartic Acid ◽  
Transcription Initiation ◽  
Amino Acid Substitutions ◽  
Conserved Residues ◽  
Acidic Residues

ABSTRACT Amino acid substitutions in Escherichia coliς70 were generated and characterized in an analysis of the role of region 1.1 in transcription initiation. Several acidic and conserved residues are tolerant of substitution. However, replacement of aspartic acid 61 with alanine results in inactivity caused by structural and functional thermolability.

scholarly journals Functional role of polar amino acid residues in Na+/H+ exchangers

2001 ◽  
Vol 357 (1) ◽  
pp. 1 ◽  
Author(s):  
Christine A. WIEBE ◽  
Emily R. DiBATTISTA ◽  
Larry FLIEGEL
Keyword(s):  
Amino Acid ◽  
Functional Role ◽  
Amino Acid Residues ◽  
Polar Amino Acid

The Functional Significance of Endocrine-immune Interactions in Health and Disease

2020 ◽  
Vol 21 (1) ◽  
pp. 52-65
Author(s):  
Sridhar Muthusami ◽  
Balasubramanian Vidya ◽  
Esaki M Shankar ◽  
Jamuna Vadivelu ◽  
Ilangovan Ramachandran ◽  
...  
Keyword(s):  
Immune System ◽  
Cell Differentiation ◽  
Amino Acid ◽  
Functional Role ◽  
Immune Cell ◽  
Amino Acid Derivatives ◽  
Endocrine Glands ◽  
Immune Systems ◽  
Health And Disease

Hormones are known to influence various body systems that include skeletal, cardiac, digestive, excretory, and immune systems. Emerging investigations suggest the key role played by secretions of endocrine glands in immune cell differentiation, proliferation, activation, and memory attributes of the immune system. The link between steroid hormones such as glucocorticoids and inflammation is widely known. However, the role of peptide hormones and amino acid derivatives such as growth and thyroid hormones, prolactin, dopamine, and thymopoietin in regulating the functioning of the immune system remains unclear. Here, we reviewed the findings pertinent to the functional role of hormone-immune interactions in health and disease and proposed perspective directions for translational research in the field.

scholarly journals Amino acid substitutions in the FXYD motif enhance phospholemman-induced modulation of cardiac L-type calcium channels

2010 ◽  
Vol 299 (5) ◽  
pp. C1203-C1211 ◽  
Author(s):  
Kai Guo ◽  
Xianming Wang ◽  
Guofeng Gao ◽  
Congxin Huang ◽  
Keith S. Elmslie ◽  
...  
Keyword(s):  
Amino Acid ◽  
Calcium Channels ◽  
Molecular Mechanisms ◽  
Channel Gating ◽  
Fine Tuning ◽  
Amino Acid Substitutions ◽  
Dependent Inactivation ◽  
Voltage Dependent ◽  
Kinetics Of

We have found that phospholemman (PLM) associates with and modulates the gating of cardiac L-type calcium channels (Wang et al., Biophys J 98: 1149–1159, 2010). The short 17 amino acid extracellular NH2-terminal domain of PLM contains a highly conserved PFTYD sequence that defines it as a member of the FXYD family of ion transport regulators. Although we have learned a great deal about PLM-dependent changes in calcium channel gating, little is known regarding the molecular mechanisms underlying the observed changes. Therefore, we investigated the role of the PFTYD segment in the modulation of cardiac calcium channels by individually replacing Pro-8, Phe-9, Thr-10, Tyr-11, and Asp-12 with alanine (P8A, F9A, T10A, Y11A, D12A). In addition, Asp-12 was changed to lysine (D12K) and cysteine (D12C). As expected, wild-type PLM significantly slows channel activation and deactivation and enhances voltage-dependent inactivation (VDI). We were surprised to find that amino acid substitutions at Thr-10 and Asp-12 significantly enhanced the ability of PLM to modulate CaV1.2 gating. T10A exhibited a twofold enhancement of PLM-induced slowing of activation, whereas D12K and D12C dramatically enhanced PLM-induced increase of VDI. The PLM-induced slowing of channel closing was abrogated by D12A and D12C, whereas D12K and T10A failed to impact this effect. These studies demonstrate that the PFXYD motif is not necessary for the association of PLM with CaV1.2. Instead, since altering the chemical and/or physical properties of the PFXYD segment alters the relative magnitudes of opposing PLM-induced effects on CaV1.2 channel gating, PLM appears to play an important role in fine tuning the gating kinetics of cardiac calcium channels and likely plays an important role in shaping the cardiac action potential and regulating Ca2+ dynamics in the heart.

Role of Chain Extension in the Ability of Peptide Oligomers to Damage the Lipid Membrane Studied by the l- to d-Amino Acid Substitutions of hIAPP18–27

2020 ◽  
Vol 124 (45) ◽  
pp. 10147-10156
Author(s):  
Feihong Meng ◽  
Tong Lu ◽  
Yajie Wang ◽  
Yanping Zhao ◽  
Zhengqiang Li ◽  
...  
Keyword(s):  
Amino Acid ◽  
Lipid Membrane ◽  
Chain Extension ◽  
Amino Acid Substitutions

scholarly journals Association Between the Rat Homologue of CO-029, a Metastasis-associated Tetraspanin Molecule and Consumption Coagulopathy

1998 ◽  
Vol 141 (1) ◽  
pp. 267-280 ◽  
Author(s):  
Christoph Claas ◽  
Simone Seiter ◽  
Andreas Claas ◽  
Larissa Savelyeva ◽  
Manfred Schwab ◽  
...  
Keyword(s):  
Amino Acids ◽  
Monoclonal Antibody ◽  
Amino Acid ◽  
Functional Role ◽  
Human Tumor ◽  
Tumor Cell Line ◽  
Metastatic Potential ◽  
Massive Bleeding ◽  
Consumption Coagulopathy

Recently, we have described a panel of metastasis-associated antigens in the rat, i.e., of molecules expressed on metastasizing, but not on nonmetastasizing tumor lines. One of these molecules, recognized by the monoclonal antibody D6.1 and named accordingly D6.1A, was found to be abundantly expressed predominantly on mesenchyme-derived cells. The DNA of the antigen has been isolated and cloned. Surprisingly, the gene product proved to interfere strongly with coagulation. The 1.182-kb cDNA codes for a 235–amino acid long molecule with a 74.2% homology in the nucleotide and a 70% homology in the amino acid sequence to CO-029, a human tumor-associated molecule. According to the distribution of hydrophobic and hydrophilic amino acids, D6.1A belongs to the tetraspanin superfamily. Western blotting of D6.1A-positive metastasizing tumor lines revealed that the D6.1A, like many tetraspanin molecules, is linked to further membrane molecules, one of which could be identified as α6β1 integrin. Transfection of a low-metastasizing tumor cell line with D6.1A cDNA resulted in increased metastatic potential and provided a clue as to the functional role of D6.1A. We noted massive bleeding around the metastases and, possibly as a consequence, local infarctions predominantly in the mesenteric region and all signs of a consumption coagulopathy. By application of the D6.1 antibody the coagulopathy was counterregulated, though not prevented. It has been known for many years that tumor growth and progression is frequently accompanied by thrombotic disorders. Our data suggest that the phenomenon could well be associated with the expression of tetraspanin molecules.

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