scholarly journals Role of tryptophan residues of Erv1: Trp95 and Trp183 are important for its folding and oxidase function

2015 ◽  
Vol 35 (4) ◽  
Author(s):  
Qi Wang ◽  
Swee Kim Ang ◽  
Efrain Ceh-Pavia ◽  
Jiayun Pang ◽  
Hui Lu
Keyword(s):  
Catalytic Domain ◽  
Tryptophan Residues ◽  
And Function ◽  
Fad Binding

Erv1 (essential for respiration and viability 1) is a FAD-dependent sulphydryl oxidase with a tryptophan-rich catalytic domain. We show that Trp95 and Trp183 are important for stabilizing the folding, FAD-binding, and function of Erv1, whilst other four tryptophan residues are not functionally important.

scholarly journals Role of Tryptophan Residues in Gramicidin Channel Organization and Function

2008 ◽  
Vol 95 (1) ◽  
pp. 166-175 ◽  
Author(s):  
Amitabha Chattopadhyay ◽  
Satinder S. Rawat ◽  
Denise V. Greathouse ◽  
Devaki A. Kelkar ◽  
Roger E. Koeppe
Keyword(s):  
Gramicidin Channel ◽  
Tryptophan Residues ◽  
And Function

scholarly journals Role of the tryptophan residues in proton-coupled folate transporter (PCFT-SLC46A1) function

2016 ◽  
Vol 311 (1) ◽  
pp. C150-C157 ◽  
Author(s):  
Mitra Najmi ◽  
Rongbao Zhao ◽  
Andras Fiser ◽  
I. David Goldman
Keyword(s):  
Lipid Membrane ◽  
Binding Pocket ◽  
Transmembrane Helices ◽  
External Loop ◽  
Substituted Cysteine Accessibility ◽  
Proximal Small Intestine ◽  
Tryptophan Residues ◽  
And Function ◽  
Location Function

The proton-coupled folate transporter (PCFT) mediates folate absorption across the brush-border membrane of the proximal small intestine and is required for folate transport across the choroid plexus into the cerebrospinal fluid. In this study, the functional role and accessibility of the seven PCFT Trp residues were assessed by the substituted-cysteine accessibility method. Six Trp residues at a lipid-aqueous interface tolerated Cys substitution in terms of protein stability and function. W85C, W202C, and W213C were accessible to N-biotinyl aminoethylmethanethiosulfonate; W48C and W299C were accessible only after treatment with dithiotreitol (DTT), consistent with modification of these residues by an endogenous thiol-reacting molecule and their extracellular location. Neither W107C nor W333C was accessible (even after DTT) consistent with their cytoplasmic orientation. Biotinylation was blocked by pemetrexed only for the W48C (after DTT), W85C, W202C residues. Function was impaired only for the W299C PCFT mutant located in the 4th external loop between the 7th and 8th transmembrane helices. Despite its aqueous location, function could only be fully preserved with Phe and, to a lesser extent, Ala substitutions. There was a 6.5-fold decrease in the pemetrexed influx Vmax and a 3.5- and 6-fold decrease in the influx Kt and Ki, respectively, for the W299S PCFT. The data indicate that the hydrophobicity of the W299 residue is important for function suggesting that during the transport cycle this residue interacts with the lipid membrane thereby impacting on the oscillation of the carrier and, indirectly, on the folate binding pocket.

Abstract P108: Circulating Matrix Metalloproteinase-2 Invades the Heart and Causes Heart Failure

Hypertension ◽  
2016 ◽  
Vol 68 (suppl_1) ◽  
Author(s):  
Alejandro F Prado ◽  
Aline Azevedo ◽  
Cibele M Prado ◽  
Larissa Pernomian ◽  
Laena Pernomian ◽  
...  
Keyword(s):  
Heart Failure ◽  
Catalytic Domain ◽  
Heart Function ◽  
Matrix Metalloproteinase 2 ◽  
Saline Control ◽  
Function Loss ◽  
And Function ◽  
Tgf Β1

Background: An increase in MMP-2 levels is reported in heart failure (HF). However the role of MMP-2 in the pathogenesis of HF remains unclear. The aim of the present study was to determine the effect of increased circulating levels of MMP-2 on heart morphology and function. Methods and Results: Purified MMP-2 catalytic domain fused to GFP (catMMP-2/GFP) or saline (control) was injected into 11-wk-old male C57BL/6 mice for four weeks. The fluorescent active protein was tracked in vivo and homed in the heart. Cardiomyocyte diameter not changed between groups (catMMP-2/GFP: 11.37 ± 0.25 μm, n=7; Control: 11.38 ± 0.13 μm, n=7; P =0.97). On the other hand, fibrosis increased in the hearts of catMMP-2/GFP mice (0.82 ± 0.05% area/field, n=7 vs Control: 0.58 ± 0.02% area/field, n=7; P< 0.05). Apoptotic stained nuclei in the left ventricle (LV) of catMMP-2/GFP injected-mice amounted to 7.24%, n=4, P<0,05, whilst the LV of control animals only exhibited 0.27%, n=4. catMMP-2/GFP localized in the heart interstitium, where increased proteolytic activity (15.13 ± 1.33 U, n=5 vs Control: 9.70 ± 0.42 U, n=5; P <0.05). Hearts of catMMP-2/GFP mice showed 25% decrease in cardiac output (13 ± 1 mL/min, n=9 vs Control: 17 ± 1 mL/min, n=9), 30% decrease in ejection fraction (40 ± 2 %, n=9 vs Control: 56 ± 2 %, n=9) and stroke volume (28 ± 2 μL, n=9 vs Control: 40 ± 2 μL, n=9), and 34% decrease in fractional shortening (18 ± 1 %, n=9 vs Control: 28 ± 1 %, n=9) ( P <0.05 for all data).Western blotting showed 40% decrease in N-cadherin in animals that received catMMP-2/GFP (0.53 ± 0.08 U, n=6 vs control: 0.89 ± 0.11 U, n=6; P <0.05). Expression of signaling proteins also changed in LV of catMMP-2/GFP mice: TGF-β1 expression increased by 30% (0.60 ± 0.07 U, n=7 vs control: 0.40 ± 0.05 U, n=7, P<0,05), pAkt/Akt decreased by 40% (0.46 ± 0.05 U, n=7 vs control: 0.76 ± 0.11 U, n=7; P <0.05), pSMAD2/total SMAD2 ratio increased (1.88 ± 0.22 U, n=6 vs control: 0.93±0.12 U, n=6, P<0,05), and pSMAD3/total SMAD3 ratio increased (1.24 ± 0.22 U, n=7 vs control: 0.33 ± 0.07 U, n=7; P <0.05). Conclusions: Circulating active MMP-2 homing to the heart interstitium degrades N-cadherin and induces TGF-β1 overexpression, leading to apoptosis, and fibrosis. This mechanism may account for heart function loss when plasma levels of MMP-2 increase.

scholarly journals Chaperone-like properties of the prodomain of TNFα-converting enzyme (TACE) and the functional role of its cysteine switch

2005 ◽  
Vol 387 (3) ◽  
pp. 797-805 ◽  
Author(s):  
Jennifer D. LEONARD ◽  
Frank LIN ◽  
Marcos E. MILLA
Keyword(s):  
Catalytic Domain ◽  
Converting Enzyme ◽  
Intracellular Degradation ◽  
Chaperone Function ◽  
Tryptophan Residues ◽  
In Trans ◽  
Factor Α ◽  
Cysteine Switch ◽  
Necrosis Factor

The prodomain of TACE [TNFα (tumour necrosis factor α)-converting enzyme] is essential for the secretion of the functional enzyme. Previously, we showed that a TACE truncate was not secreted in the absence of the prodomain and that it was subjected to intracellular degradation. In the present study, we show that full-length TACE was also degraded when expressed without the prodomain. We demonstrate that the prodomain can rescue TACE's secretion in trans, suggesting an intramolecular chaperone function. We addressed the question whether a cysteine switch consensus motif is needed for the secretion of active TACE. The cysteine switch mutants [C184A (Cys184→Ala)] of TACE resembled the wild-type functionally and in their sensitivity to inhibitors. Interestingly, TACE zymogen forms expressed in the context of the C184A mutation were susceptible to intracellular degradation, suggesting that the prodomain-bound TACE zymogen may be more accessible to intracellular proteinases when compared with mature TACE. Two independent findings confirmed that the catalytic domain of TACE is in a more open state when bound to its prodomain: (i) core tryptophan residues were exposed to the solvent in the procatalytic domain complex and (ii) LysC rapidly proteolysed the procatalytic domain complex but not mature TACE. Therefore the prodomain of TACE is a specific intramolecular chaperone that aids in the secretion of this enzyme, while keeping the catalytic domain in a relatively open conformation. The cysteine switch of TACE is not essential for the secretion of the functional enzyme, but may prevent intracellular degradation of the TACE zymogen.

scholarly journals Structure of Mycobacterium tuberculosis Cya, an evolutionary ancestor of the mammalian membrane adenylyl cyclases

2021 ◽  
Author(s):  
Ved Mehta ◽  
Basavraj Khanppnavar ◽  
Dina Schuster ◽  
Irene Vercellino ◽  
Angela Kosturanova ◽  
...  
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Catalytic Activity ◽  
Adenylyl Cyclase ◽  
Catalytic Domain ◽  
Transmembrane Domain ◽  
Vital Role ◽  
Cytosolic Side ◽  
Tm Domain ◽  
And Function

AbstractMycobacterium tuberculosis adenylyl cyclase (AC) Cya is an evolutionary ancestor of the mammalian membrane ACs and a model system for studies of their structure and function. Although the vital role of ACs in cellular signaling is well established, the function of their transmembrane (TM) regions remains unknown. Here we describe the cryo-EM structure of Cya bound to a stabilizing nanobody at 3.6 Å resolution. The TM helices 1-5 form a structurally conserved domain that facilitates the assembly of the helical and catalytic domains. The TM region contains discrete pockets accessible from the extracellular and cytosolic side of the membrane. Neutralization of the negatively charged extracellular pocket Ex1 destabilizes the cytosolic helical domain and reduces the catalytic activity of the enzyme. The TM domain acts as a functional component of Cya, guiding the assembly of the catalytic domain and providing the means for direct regulation of catalytic activity in response to extracellular ligands.One-Sentence SummaryCryo-EM structure of M. tuberculosis adenylyl cyclase Cya provides clues to the role of its transmembrane domain

scholarly journals A topologically distinct class of photolyases specific for UV lesions within single-stranded DNA

2020 ◽  
Vol 48 (22) ◽  
pp. 12845-12857
Author(s):  
Hans-Joachim Emmerich ◽  
Martin Saft ◽  
Leonie Schneider ◽  
Dennis Kock ◽  
Alfred Batschauer ◽  
...  
Keyword(s):  
Flavin Adenine Dinucleotide ◽  
Catalytic Domain ◽  
Sequence Similarity ◽  
Bacterial Species ◽  
Single Stranded Dna ◽  
Dna Damages ◽  
Terminal Domain ◽  
And Function ◽  
Uv Lesions ◽  
Fad Binding

Abstract Photolyases are ubiquitously occurring flavoproteins for catalyzing photo repair of UV-induced DNA damages. All photolyases described so far have a bilobal architecture with a C-terminal domain comprising flavin adenine dinucleotide (FAD) as catalytic cofactor and an N-terminal domain capable of harboring an additional antenna chromophore. Using sequence-similarity network analysis we discovered a novel subgroup of the photolyase/cryptochrome superfamily (PCSf), the NewPHLs. NewPHL occur in bacteria and have an inverted topology with an N-terminal catalytic domain and a C-terminal domain for sealing the FAD binding site from solvent access. By characterizing two NewPHL we show a photochemistry characteristic of other PCSf members as well as light-dependent repair of CPD lesions. Given their common specificity towards single-stranded DNA many bacterial species use NewPHL as a substitute for DASH-type photolyases. Given their simplified architecture and function we suggest that NewPHL are close to the evolutionary origin of the PCSf.

scholarly journals Role of Tryptophan Residues in Toxicity of Cry1Ab Toxin from Bacillus thuringiensis

2006 ◽  
Vol 72 (1) ◽  
pp. 901-907 ◽  
Author(s):  
Cristopher Padilla ◽  
Liliana Pardo-López ◽  
Gustavo de la Riva ◽  
Isabel Gómez ◽  
Jorge Sánchez ◽  
...  
Keyword(s):  
Bacillus Thuringiensis ◽  
Insecticidal Activity ◽  
Structural Changes ◽  
Site Directed Mutagenesis ◽  
Crystal Formation ◽  
Cry Toxins ◽  
Tryptophan Residues ◽  
Cry1ab Toxin ◽  
And Function

ABSTRACT Bacillus thuringiensis produces insecticidal proteins (Cry protoxins) during the sporulation phase as parasporal crystals. During intoxication, the Cry protoxins must change from insoluble crystals into membrane-inserted toxins which form ionic pores. The structural changes of Cry toxins during oligomerization and insertion into the membrane are still unknown. The Cry1Ab toxin has nine tryptophan residues; seven are located in domain I, the pore-forming domain, and two are located in domain II, which is involved in receptor recognition. Eight Trp residues are highly conserved within the whole family of three-domain Cry proteins, suggesting an essential role for these residues in the structural folding and function of the toxin. In this work, we analyzed the role of Trp residues in the structure and function of Cry1Ab toxin. We replaced the Trp residues with phenylalanine or cysteine using site-directed mutagenesis. Our results show that W65 and W316 are important for insecticidal activity of the toxin since their replacement by Phe reduced the toxicity against Manduca sexta. The presence of hydrophobic residue is important at positions 117, 219, 226, and 455 since replacement by Cys affected either the crystal formation or the insecticidal activity of the toxin in contrast to replacement by Phe in these positions. Additionally, some mutants in positions 219, 316, and 455 were also affected in binding to brush border membrane vesicles (BBMV). This is the first report that studies the role of Trp residues in the activity of Cry toxins.

Scanning electron microscopic study of collagen fibrillogenesis and extracellular compartmentalization in the chick embryo tendon

1986 ◽  
Vol 44 ◽  
pp. 208-209
Author(s):  
Grace C.H. Yang
Keyword(s):  
Chick Embryo ◽  
Extracellular Space ◽  
Fibroblast Cell ◽  
Collagen Fibrils ◽  
Electron Microscopic ◽  
Voltage Electron ◽  
Scanning Electron Microscopic Study ◽  
Microscopic Studies ◽  
And Function

The size and organization of collagen fibrils in the extracellular matrix is an important determinant of tissue structure and function. The synthesis and deposition of collagen involves multiple steps which begin within the cell and continue in the extracellular space. High-voltage electron microscopic studies of the chick embryo cornea and tendon suggested that the extracellular space is compartmentalized by the fibroblasts for the regulation of collagen fibril, bundle, and tissue specific macroaggregate formation. The purpose of this study is to gather direct evidence regarding the association of the fibroblast cell surface with newly formed collagen fibrils, and to define the role of the fibroblast in the control and the precise positioning of collagen fibrils, bundles, and macroaggregates during chick tendon development.

Role of the Cilia Membrane in Control of Microtubule Sliding

1980 ◽  
Vol 38 ◽  
pp. 612-615
Author(s):  
Edna S. Kaneshiro
Keyword(s):  
Control Mechanism ◽  
Beat Frequency ◽  
Surface Membrane ◽  
Ciliary Membrane ◽  
Ciliary Beating ◽  
Ciliary Reversal ◽  
Voltage Dependent ◽  
Reversal Mechanism ◽  
And Function

It is currently believed that ciliary beating results from microtubule sliding which is restricted in regions to cause bending. Cilia beat can be modified to bring about changes in beat frequency, cessation of beat and reversal in beat direction. In ciliated protozoans these modifications which determine swimming behavior have been shown to be related to intracellular (intraciliary) Ca2+ concentrations. The Ca2+ levels are in turn governed by the surface ciliary membrane which exhibits increased Ca2+ conductance (permeability) in response to depolarization. Mutants with altered behaviors have been isolated. Pawn mutants fail to exhibit reversal of the effective stroke of ciliary beat and therefore cannot swim backward. They lack the increased inward Ca2+ current in response to depolarizing stimuli. Both normal and pawn Paramecium made leaky to Ca2+ by Triton extrac¬tion of the surface membrane exhibit backward swimming only in reactivating solutions containing greater than IO-6 M Ca2+ Thus in pawns the ciliary reversal mechanism itself is left operational and only the control mechanism at the membrane is affected. The topographic location of voltage-dependent Ca2+ channels has been identified as a component of the ciliary mem¬brane since the inward Ca2+ conductance response is eliminated by deciliation and the return of the response occurs during cilia regeneration. Since the ciliary membrane has been impli¬cated in the control of Ca2+ levels in the cilium and therefore is the site of at least one kind of control of microtubule sliding, we have focused our attention on understanding the structure and function of the membrane.

Sign in / Sign up

Export Citation Format

Share Document