Heparan sulphate N-sulphotransferase activity: reaction mechanism and substrate recognition

2003 ◽  
Vol 31 (2) ◽  
pp. 331-334 ◽  
Author(s):  
Y. Kakuta ◽  
L. Li ◽  
L.C. Pedersen ◽  
L.G. Pedersen ◽  
M. Negishi
Keyword(s):  
Active Site ◽  
Transfer Reaction ◽  
Substrate Recognition ◽  
Heparan Sulphate ◽  
Critical Role ◽  
Random Coil ◽  
Group Transfer ◽  
Α Helix ◽  
Model Chain

Human heparan sulphate N-deacetylase/N-sulphotransferase 1 sulphates the NH3+ group of the glucosamine moiety of the heparan chain in heparan sulphate/heparin biosynthesis. An open cleft that runs perpendicular to the sulphate donor 3´-phosphoadenosine 5´-phosphosulphate may constitute the acceptor substrate-binding site of the sulphotransferase domain (hNST1) [Kakuta, Sueyoshi, Negishi and Pedersen (1999) J. Biol. Chem. 274, 10673–10676]. When a hexasaccharide model chain is docked into the active site, only a trisaccharide (-IdoA-GlcN-IdoA-) portion interacts directly with the cleft residues: Trp-713, His-716 and His-720 from α helix 6, and Phe-640, Glu-641, Glu-642, Gln-644 and Asn-647 from random coil (residues 640–647). Mutation of these residues either abolishes or greatly reduces hNST1 activity. Glu-642 may play the critical role of catalytic base in the sulphuryl group transfer reaction, as indicated by its hydrogen-bonding distance to the NH3+ group of the glucosamine moiety in the model and by mutational data.

Cationicity and hydrophobicity enhance the cytotoxic potency of Phoratoxin C anticancer peptide analogues against triple negative breast cancer cells

2021 ◽  
Vol 17 ◽  
Author(s):  
Chu Xin Ng ◽  
Cheng Foh Le ◽  
Sau Har Lee
Keyword(s):  
Cancer Cells ◽  
Anticancer Agents ◽  
Breast Cancer Cells ◽  
Critical Role ◽  
Three Dimensional ◽  
Vero Cells ◽  
Anticancer Peptides ◽  
Α Helix ◽  
Peptide Analogues

Background: Anticancer peptides (ACPs) have received increasing attention as a promising class of novel anticancer agents owing to its potent and rapid cytotoxic properties. In this study, we aim to investigate the effects of cationicity and hydrophobicity in modulating the cytotoxicity of PtxC, a class of ACP from the leafy mistletoe Phoradendron tomentosum against the MDA-MB-231 and Vero cells. Method: We designed a series of four PtxC analogues (PA1 – PA4) by residual substitutions with specific amino acids to introduce the specific charge and hydrophobicity alterations to the analogues. The cytotoxicity strength of the PtxC analogues on MDA-MB-231 and Vero cells were tested by using MTT assay at 24 hours post treatment. Results: PA1, PA2 and PA4 displayed marked increases in cytotoxicity against both MDA-MB-231 and Vero cells and can be ranked in the order of PA2 > PA4 > PA1 > PtxC > PA3. Sequence-activity relationship analyses of the designed analogues showed that an increase in the level of cationicity and hydrophobicity correlated well with the enhanced cytotoxic activity of PtxC analogues. This was observed with PA1 (netC +8) and PA2 (netC +10) in comparison to PtxC (netC +7). Similar finding was observed for PA4 (GRAVY +0.070) in contrast to PtxC (GRAVY -0.339). Three-dimensional modelling predicted a double α-helix structure in PtxC class of ACP. The larger first helix in PA2 and PA4 was suggested to be responsible for the enhanced cytotoxicity observed. Conclusion: The critical role of cationicity and hydrophobicity in enhancing cytotoxicity of PtxC class of ACPs were clearly demonstrated in our study. The current findings could be extrapolated to benefit peptide design strategy in other classes of ACPs toward the discovery of highly potent ACPs against cancer cells as potential novel therapeutic agents.

Role of active site arginine residues in substrate recognition by PPM1A

2021 ◽  
Author(s):  
Itsumi Tani ◽  
Shogo Ito ◽  
Yukiko Shirahata ◽  
Yutaka Matsuyama ◽  
James G. Omichinski ◽  
...  
Keyword(s):  
Active Site ◽  
Substrate Recognition ◽  
Arginine Residues

Unveiling the critical role of active site interaction in single atom catalyst towards hydrogen evolution catalysis

Nano Energy ◽  
2022 ◽  
Vol 93 ◽  
pp. 106819
Author(s):  
Feng Li ◽  
Gao-Feng Han ◽  
Yunfei Bu ◽  
Shanshan Chen ◽  
Ishfaq Ahmad ◽  
...  
Keyword(s):  
Hydrogen Evolution ◽  
Active Site ◽  
Critical Role ◽  
Single Atom

scholarly journals Albino mutants of Streptomyces glaucescens tyrosinase

1991 ◽  
Vol 274 (3) ◽  
pp. 707-713 ◽  
Author(s):  
M P Jackman ◽  
A Hajnal ◽  
K Lerch
Keyword(s):  
Active Site ◽  
Critical Role ◽  
Site Directed Mutagenesis ◽  
Mutant Proteins ◽  
Carbonyl Derivatives ◽  
Hydrogen Bonding Interactions ◽  
Albino Phenotype ◽  
Derivatives Of ◽  
Streptomyces Glaucescens

Site-directed mutagenesis was used to determine the functional role of several residues of Streptomyces glaucescens tyrosinase. Replacement of His-37, -53, -193 or -215 by glutamine yields albino phenotypes, as determined by expression on melanin-indicator plates. The purified mutant proteins display no detectable oxy-enzyme and increased Cu lability at the binuclear active site. The carbonyl derivatives of H189Q and H193Q luminesce, with lambda max. displaced more than 25 nm to a longer wavelength compared with native tyrosinase. The remaining histidine mutants display no detectable luminescence. The results are consistent with these histidine residues (together with His-62 and His-189 reported earlier) acting as Cu ligands in the Streptomyces glaucescens enzyme. Conservative substitution of the invariant Asn-190 by glutamine also gives an albino phenotype, no detectable oxy-enzyme and labilization of active-site Cu. The luminescence spectrum of carbonyl-N190Q, however, closely resembles that of the native enzyme under conditions promoting double Cu occupancy of the catalytic site. A critical role for Asn-190 in active-site hydrogen-bonding interactions is proposed.

Critical role of a conserved transmembrane lysine in substrate recognition by the proton-coupled oligopeptide transporter YjdL

2014 ◽  
Vol 55 ◽  
pp. 311-317 ◽  
Author(s):  
Johanne M. Jensen ◽  
Nanda G. Aduri ◽  
Bala K. Prabhala ◽  
Rasmus Jahnsen ◽  
Henrik Franzyk ◽  
...  
Keyword(s):  
Substrate Recognition ◽  
Critical Role ◽  
Oligopeptide Transporter

scholarly journals New insights into the mechanism of substrates trafficking in Glyoxylate/Hydroxypyruvate reductases

2016 ◽  
Vol 6 (1) ◽  
Author(s):  
Louise Lassalle ◽  
Sylvain Engilberge ◽  
Dominique Madern ◽  
Pierre Vauclare ◽  
Bruno Franzetti ◽  
...  
Keyword(s):  
Renal Failure ◽  
Active Site ◽  
Ternary Complex ◽  
Substrate Recognition ◽  
Binding Mode ◽  
X Ray ◽  
Hyperoxaluria Type

Abstract Glyoxylate accumulation within cells is highly toxic. In humans, it is associated with hyperoxaluria type 2 (PH2) leading to renal failure. The glyoxylate content within cells is regulated by the NADPH/NADH dependent glyoxylate/hydroxypyruvate reductases (GRHPR). These are highly conserved enzymes with a dual activity as they are able to reduce glyoxylate to glycolate and to convert hydroxypyruvate into D-glycerate. Despite the determination of high-resolution X-ray structures, the substrate recognition mode of this class of enzymes remains unclear. We determined the structure at 2.0 Å resolution of a thermostable GRHPR from Archaea as a ternary complex in the presence of D-glycerate and NADPH. This shows a binding mode conserved between human and archeal enzymes. We also determined the first structure of GRHPR in presence of glyoxylate at 1.40 Å resolution. This revealed the pivotal role of Leu53 and Trp138 in substrate trafficking. These residues act as gatekeepers at the entrance of a tunnel connecting the active site to protein surface. Taken together, these results allowed us to propose a general model for GRHPR mode of action.

Critical Role of Val567 in Substrate Recognition by Neuronal Nitric Oxide Synthase for NO Formation Activity

2003 ◽  
Vol 32 (11) ◽  
pp. 998-999 ◽  
Author(s):  
Hiroto Takahashi ◽  
Yuko Sato ◽  
Magoli Moreau ◽  
Marie-Agnes Sari ◽  
Jean-Luc Boucher ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Nitric Oxide Synthase ◽  
Substrate Recognition ◽  
Critical Role ◽  
Neuronal Nitric Oxide Synthase ◽  
No Formation ◽  
Oxide Synthase

scholarly journals Structural and Functional Determinants of Conserved Lipid Interaction Domains of Inward Rectifying Kir6.2 Channels

2002 ◽  
Vol 119 (6) ◽  
pp. 581-591 ◽  
Author(s):  
Catherine A. Cukras ◽  
Iana Jeliazkova ◽  
Colin G. Nichols
Keyword(s):  
Critical Role ◽  
Katp Channels ◽  
Pleckstrin Homology Domain ◽  
Membrane Association ◽  
Kir Channel ◽  
M1 Receptor ◽  
Interaction Domains ◽  
Mechanistic Basis ◽  
Α Helix

All members of the inward rectifiier K+ (Kir) channel family are activated by phosphoinositides and other amphiphilic lipids. To further elucidate the mechanistic basis, we examined the membrane association of Kir6.2 fragments of KATP channels, and the effects of site-directed mutations of these fragments and full-length Kir6.2 on membrane association and KATP channel activity, respectively. GFP-tagged Kir6.2 COOH terminus and GFP-tagged pleckstrin homology domain from phospholipase C δ1 both associate with isolated membranes, and association of each is specifically reduced by muscarinic m1 receptor–mediated phospholipid depletion. Kir COOH termini are predicted to contain multiple β-strands and a conserved α-helix (residues ∼306–311 in Kir6.2). Systematic mutagenesis of D307-F315 reveals a critical role of E308, I309, W311 and F315, consistent with residues lying on one side of a α-helix. Together with systematic mutation of conserved charges, the results define critical determinants of a conserved domain that underlies phospholipid interaction in Kir channels.

Sign in / Sign up

Export Citation Format

Share Document