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PubMedDate not supplied

[Role of lysine binding sites in activation of plasminogen by streptokinase].

The function of lysine-binding sites in kringle domains K1-4 and K5 of plasminogen (Pg) during its activation by streptokinase (SK) was studied. Activation rates of Glu- and Lys-Pg exceed activation rate of mini- and micro-Pg 26 and 40 times, respectively. 6-Animohexanoic acid (6-AHA) in concentrations from 10(-5) to 10(-2) M inhibits activation of Glu-, Lys- and mini-Pg and does not impact the activation of micro-Pg. Complete inhibition of Lys-Pg activation occurs with presence of 10(-3) M 6-AHA while 90% inhibition of mini-Pg activation and 70% inhibition of Glu-Pg activation occur with 10(-2) M 6-AHA. Isolated kringles K1-3 and K4 of Pg inhibit activation of Glu-Pg by SK and concentrations [I]50 are 4.0 and 8.1 x 10(-6) M, respectively. Catalytic activity of Glu-Pg-SK, Lys-Pg-SK and Pm-SK complexes with respect to S 2251 is not inhibited by 6-AHA in concentrations from 10(-5) to 10(-2) M. Activation of substrate Pg by Pm-SK complex is also inhibited by 6-AHA in concentrations from 10(-5) to 10(-2) M; however, this effect of inhibition is significantly weaker than that with activation by SK. Cleavage of C-terminal Lys or chemical modification of NH2-groups of amino acid residues in SK molecule also results in the decrease of the Glu-Pg activation rate. Lysin-binding sites in K1-4 and K5 of Pg molecule are important at different steps of Pg activation process which includes formation of equimolar complex; structural reorganizations resulted in formation of active center in Pg; and binding of substrate Pg with Pg-SK complex. Lysin-binding sites in K1-4 of Pg are necessary for maintenance of high rate of Pg activation by SK.

Aminocaproic Acid↗
PubMed1999

Inhibition mechanism of cathepsin L-specific inhibitors based on the crystal structure of papain-CLIK148 complex.

Papain was used as an experimental model structure to understand the inhibition mechanism of newly developed specific inhibitors of cathepsin L, the papain superfamily. Recently, we developed a series of cathepsin L-specific inhibitors which are called the CLIK series [(1999) FEBS Lett. 458, 6-10]. Here, we report the complex structure of papain with CLIK148, which is a representative inhibitor from the CLIK series. The inhibitor complex structure was solved at 1.7 A resolution with conventional R 0.177. Unlike other epoxisuccinate inhibitors (E64, CA030, and CA074), CLIK148 uses both prime and nonprime sites, which are important for the specific inhibitory effect on cathepsin L. Also, the specificity for cathepsin L could be explained by the existence of Phe in the P2 site and hydrophobic interaction of N-terminal pyridine ring.

Cathepsin L↗
PubMed2006

fac-[Re(CO)3(dmso-O)3](CF3SO3): a new versatile and efficient Re(I) precursor for the preparation of mono and polynuclear compounds containing fac-[Re(CO)3]+ fragments.

We show here that the new complex fac-[Re(CO)3(dmso-O)3](CF3SO3) (1), efficiently prepared in one step from [ReBr(CO)5] and featuring a broad range of solubility, is, in general, a better precursor for the one-step synthesis of mono- and polynuclear inorganic compounds containing fac-[Re(CO)3]+ fragments compared to the commonly used (NEt4)2fac-[ReBr3(CO)3] and fac-[Re(CO)3(CH3CN)3](Y) (Y = PF6, BF4, ClO4) species. Compound 1 is the first example of a Re(I)-dmso complex structurally characterized and confirms the rule that dmso is always O-bonded when trans to CO. The reactivity of 1 was tested in the one-step preparation of several new and known complexes. The O-bonded sulfoxides of 1 are replaced under mild conditions by tri- (L3) and bidentate ligands (L2) to produce fac-[Re(CO)3(L3)]+ and fac-[Re(CO)3(L2)(dmso-O)]+ compounds, respectively. An excess of monodentate ligands (L) and more forcing conditions are needed to prepare fac-[Re(CO)3(L)3]+ compounds. The new compounds include fac-[Re(CO)3(bipy)(dmso-O)](CF3SO3) (4), that turned out to be an excellent precursor for binding the luminescent fac-[Re(CO)3(bipy)]+ fragment to polytopic ligands for the construction of more elaborate assemblies. One example reported here is the two-step preparation of fac-[{Re(CO)3(bipy)}(mu-4,4'-bipy){Ru(TPP)(CO)}](CF3SO3) (8) (TPP = tetraphenylporphyrin). The X-ray structures of the new compounds 1, 4, of the bis-porphyrin complex fac-[Re(CO)3Cl(4'MPyP)2] (13) (4'MPyP = 5-(4'pyridyl)-10,15,20-triphenylporphyrin), and of the rhenium-cyclophane [{(CO)3Re(mu-OH)2Re(CO)3}2(micro-4,4'-bipy)2] (15), among others, are described. Compound 1 might find useful applications in supramolecular chemistry (metal-mediated assembly of large architectures), in the in situ preparation of stable Re compounds to be used in nuclear medicine, and for the labeling of biomolecules.

Journal Article↗
PubMed1996

Structure of a ribonuclease B+d(pA)4 complex.

The structure of a tetragonal crystal of bovine pancreatic RNase B complexed with d(pA)(4) was determined by molecular replacement and difference Fourier methods. This crystal belongs to space group P4(1)2(1)2 and has unit-cell dimensions a = b = 44.5, c = 156.5 A. The model consists of the enzyme and a tetranucleotide with fractional occupancies, suggesting multiple modes of oligonucleotide binding. It does not include any polysaccharide residues or solvent molecules. After refinement at 2.7 A, the R value was 0.163 with acceptable stereochemistry. The model illustrates a set of well defined interactions for substrate binding, particularly between the central dinucleotide and the enzyme.

Journal Article↗
PubMed2001

X-ray diffraction evidence for the lack of stereospecific protein interactions in highly activated actomyosin complex.

The structure of actomyosin complex while hydrolyzing ATP was investigated by recording X-ray diffraction patterns from rabbit skeletal muscle fibers, in which exogenously introduced rabbit skeletal subfragment-1 (S1) was covalently cross-linked to the endogenous actin filaments in rigor by 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC). Approximately two-thirds of the introduced S1 was cross-linked. The cross-linking procedure did not affect the profile of the S1-induced enhancement of the actin-based layer line reflections in rigor, indicating that the acto-S1 interactions remained highly stereospecific. In the presence of ATP, the MgATPase of the S1 was highly activated regardless of calcium levels, presumably because the availability of the stereospecific binding sites for both proteins was maximized by the cross-linking. However, the diffraction pattern in the presence of ATP was striking in that the intensity profile of the strong 1/5.9 nm(-1) layer lines was indistinguishable from that from bare actin filaments, despite the fact that the majority of the S1 was still associated with actin. The change of the intensity profiles upon addition of ATP was completely reversible. Model calculations showed that this result can be explained if the S1 is not only swinging around its pivoting point, but the pivoting point itself is also moving on the actin surface in a range of a few nanometers. The results suggest that the stereospecific binding sites, which have been considered important for actomyosin cycling, are paradoxically left unoccupied for most of the time in this highly activated actomyosin complex.

Actins↗
PubMed1999

Synthesis and Structural Characterization of Neutral Silver(I) Complexes with Arenephosphinothiols. Crystal Structures of [Ag(4){2-(Ph(2)P)-6-(Me(3)Si)C(6)H(6)S}(4)] and [Ag(4){2-(Ph(2)PO)-6-(Me(3)Si)C(6)H(3)S}(4)].

Silver complexes of the anionic forms of 2-(diphenylphosphino)benzenethiol [2-(Ph(2)P)C(6)H(4)SH] (1), 2-(diphenylphosphino)-6-(trimethylsilyl)benzenethiol [2-(Ph(2)P)-6-(Me(3)Si)C(6)H(3)SH] (2), and 2-(diphenylphosphinyl)-6-(trimethylsilyl)benzenethiol [2-(Ph(2)PO)-6-(Me(3)Si)C(6)H(3)SH] (3) have been prepared by an electrochemical procedure and characterized by spectroscopic (IR, (1)H, (13)C, and (31)P NMR) methods, and ligand 3 and [Ag(4){2-(Ph(2)P)-6-(Me(3)Si)C(6)H(3)S}(4)] (5) and [Ag(4){2-(Ph(2)PO)-6-(Me(3)Si)C(6)H(3)S}(4)] (6) complexes were characterized by X-ray crystallographic techniques. Crystal data for 3: C(21)H(23)OPSSi, monoclinic, P2(1)/n, a = 11.3730(4) Å, b = 11.1562(4) Å, c = 17.1153(6) Å, beta = 103.961(1) degrees, V = 2107.4(1) Å(3), Z = 4, 2730 reflections with I(o) > 2sigma(I(o)), R = 0.0621. Crystal data for 5: C(84)H(88)Ag(4)P(4)S(4)Si(4), tetragonal, P4(2)2(1)2, a = 18.8454(7) Å, b = 18.8454(7) Å, c = 24.596(2) Å, V = 8735.1(7) Å(3), Z = 4, 4676 reflections with I(o) > 2sigma(I(o)), R = 0.0286. Crystal data for 6: C(90)H(97)Ag(4)N(3)O(4)P(4)S(4)Si(4), trigonal, P1, a = 13.4567(1) Å, b = 14.4148(2) Å, c = 14.8080(2) Å, alpha = 99.130(1) degrees, beta = 98.815(1) degrees, g = 114.211(1) degrees, V = 2509.38(5) Å(3), Z = 1, 6345 reflections with I(o) > 2sigma(I(o)), R = 0.0505. The [Ag(4){2-(Ph(2)P)-6-(Me(3)Si)C(6)H(3)S}(4)] (5) compound is tetranuclear with an array of four silver atoms bridged by four sulfur atoms. Each silver atom has a distorted trigonal [AgS(2)P] environment with each ligand acting as P,S bidentate S-bridging ligand. The [Ag(4)(2-(Ph(2)PO)-6-(Me(3)Si)C(6)H(3)S}(4)] (6) complex is also tetranuclear, but in this case two of the silver atoms are [AgO(2)S(2)] tetracoordinated and the other two Ag atoms are [AgS(2)] two coordinated.

Journal Article↗
PubMed2004

Molecular simulation evidence for solidlike adsorbate in complex carbonaceous micropore structures.

Adsorption of a model nitrogen vapor on a range of complex nanoporous carbon structures is simulated by grand canonical Monte Carlo simulation for a single subcritical temperature above the bulk freezing point. Adsorption and desorption isotherms, heats of adsorption, and three-dimensional singlet distribution functions (SDFs) were generated. Inspection of the SDFs reveals significant levels of solidlike adsorbate at saturation even in the most complex of the microporous solids considered. This strongly suggests that solidlike adsorbate will also occur for simple subcritical vapors adsorbed on real noncrystalline solids such as microporous carbons at temperatures above the bulk freezing point, supporting indirect experimental observations. The presence of significant levels of solidlike adsorbate has implications for characterization of microporous solids where adsorbate density is used (e.g., determination of pore volume from loading). Detailed consideration of the SDF at different loadings for a model microporous solid indicates solidlike adsorbate forms at distributed points throughout the pore space at pressures dependent on the nature of the local porosity. The nature of the local porosity also dictates the freezing mechanism. A local freezing/ melting/refreezing process is also observed. Introduction of mesoporosity into the model causes hysteresis between the adsorption and desorption isotherms. Adsorption in the hysteresis loop occurs by a series of local condensation events. It appears as if the presence of adjacent microporosity and/or adsorbate within it affects the pressure at which these events occur. Reversal of the condensation during desorption occurs throughout the mesoporosity at a single pressure; this pressure is unaffected by the presence of adjacent microporosity or the adsorbate within it. It is also shown that the empirical concept of "pore size" is not consistent for describing adsorption in the complex solids considered here. A new concept is, therefore, proposed that seeks to account for the factors that affect local adsorption energy: local geometry, microtexture, surface atom density, and surface chemistry.

Journal Article↗
PubMed1988

Preparation and use of synthetic blood group specific immunoadsorbents.

The carbohydrate structures determining the ABO blood group system have been almost completely characterized. Recent advances in the stereoselective synthesis of such complex structures have made it possible to prepare pure oligosaccharides in large quantities and to study their possible uses for diagnostics and pharmaceutical processing techniques. In the experiments described here A and B blood group specific determinants were synthesized and bound to solid phases by means of suitable spacers in order to study their use as immunoadsorbents. The objective was to adsorb blood group specific antibodies from positive sera and from immunoglobulin preparations. It was shown that the anti-A and anti-B antibodies bound to the immunoadsorbents with high affinity could be removed effectively. The effects were achieved both using affinity chromatography and "batch processing".

ABO Blood-Group System↗
PubMed1998

Glycoproteins and their relationship to human disease.

Glycoproteins are proteins that carry N- and O-glycosidically-linked carbohydrate chains of complex structures and functions. N-glycan chains are assembled in the endoplasmic reticulum and the Golgi by a controlled sequence of glycosyltransferase and glycosidase processing reactions involving dolichol intermediates. The assembly of O-glycans occurs in the Golgi and does not involve dolichol. For most reactions, families of glycosyltransferases exist; the expression of the individual enzymes within a family is often subject to complex regulation. The biosynthesis of N- and O-glycan is controlled at the level of gene expression, mRNA, enzyme protein activity and localization, and through substrate and cofactor concentrations at the site of synthesis. This complex regulation results in many hundreds of structures, the range of which varies in different species, cell types, tissue types, states of development and differentiation. In diseased cells, the relative proportions of these structures are often characteristically different from normal, and may be useful for the assessment of the stage of the disease and for diagnosis. Knowledge of disease-specific glycoprotein structures and their functions may be used therapeutically, in immunotherapy, in blocking cell adhesion or interfering with other binding or biological processes. Recently, some of the mechanisms underlying glycoprotein alterations in disease have been elucidated. This opens the possibility of an active interference in the disease process. The functions of glycans in diseased cells will become more clear with the tools of molecular biology and transgenic animal models.

Animals↗
PubMed1988

Binding of 9-aminoacridine to bulged-base DNA oligomers from a frame-shift hot spot.

Complexes of 9-aminoacridine and two derivatives with oligomers based on the sequence of a hot spot for frame-shift mutations, 5'dGATGGGGCAG, are investigated by proton NMR and equilibrium dialysis. Competition dialysis experiments show that the drug binds bulge-containing oligomers more strongly than regular duplexes of similar sequence and length, with one apparent strong site. A duplex containing an extra cytidine in a run of C's has the highest affinity for 9-aminoacridine among the sequences tested. An oligomer containing five consecutive G.C pairs shows cooperative drug binding, indicating that G tracts of this length may have an altered helical structure. Complexes of a regular 8-mer and a 9-mer containing a bulged guanosine are examined in detail by two-dimensional NMR techniques. 9-Aminoacridine preferentially binds at TpG sites in the 8-mer but binds primarily at the bulged guanosine in the G-bulge 9-mer. Drug-DNA NOE's in the 8-mer complex are compared with the crystal structure of 9-aminoacridine and 5-iodo-CpG [Sakore et al. (1979) J. Mol. Biol. 135, 763-785]. The NMR data suggest that the drug intercalates across the base pairs of both strands with the amino group projecting into the minor groove.

Aminacrine↗
PubMed1980

The structure of segments of the anisotropic band of muscle. II. Preparation and properties of A segments from vertebrate skeletal muscle.

The anisotropic band of skeletal muscle is a complex structural assembly of the protein myosin and associated nonmyosin components. To study the relationships among these proteins, aggregates of thick myofilaments held together at the M line (A segments) have been prepared from fresh and glycerol extracted chicken pectoralis and rabbit psoas muscles and from fresh frog sartorius muscle. The structure of the A segments included several thick filaments, an M line, and a bare zone or pseudo-H zone, lateral to the M line. Most of the A segments exhibited a pattern of eleven periodic stripes in each half lateral to the bare zone. The A segments from fresh muscle displayed these stripes more consistently than did the A segments from glycerinated muscle. Some of the major stripes appeared to be double, and there were two subdivisions between the stripes nearest the bare zone. The more lateral of the major A band stripes, however, had one subdivision between them. The M line consisted of three prominent medial stripes and two fainter lateral stripes. In the M lines of rabbit A segments the lateral stripes were located well into the bare zone whereas the lateral stripes of M lines in chicken A segments were closer to the three medial M line stripes. Our results on the preparation and properties of A segments are compared with those of of the investigators.

Animals↗
PubMed1994

Size dependency of circular dichroism in macroaggregates of photosynthetic pigment-protein complexes.

Large molecular aggregates, condensed biological macromolecules, intact membrane systems, and cell organelles often exhibit intense anomalous circular dichroism (CD) bands which are absent in systems of lower structural complexity. Theory predicts that in dense, chirally organized macroaggregates the size of the aggregate controls the magnitude of the anomalous CD bands [Keller, D., & Bustamante, C. (1986) J. Chem. Phys. 84, 2972-2979]. Photosynthetic pigment-protein complexes in their native thylakoid membranes and in vitro were used to provide direct experimental evidence of the size dependency of CD in macroaggregates.

Chlorophyll↗
PubMed1997

Structure and function of the xenobiotic substrate-binding site and location of a potential non-substrate-binding site in a class pi glutathione S-transferase.

Complex structures of a naturally occurring variant of human class pi glutathione S-transferase 1-1 (hGSTP1-1) with either S-hexylglutathione or (9R,10R)-9-(S-glutathionyl)-10-hydroxy-9, 10-dihydrophenanthrene [(9R,10R)-GSPhen] have been determined at resolutions of 1.8 and 1.9 A, respectively. The crystal structures reveal that the xenobiotic substrate-binding site (H-site) is located at a position similar to that observed in class mu GST 1-1 from rat liver (rGSTM1-1). In rGSTM1-1, the H-site is a hydrophobic cavity defined by the side chains of Y6, W7, V9, L12, I111, Y115, F208, and S209. In hGSTP1-1, the cavity is approximately half hydrophobic and half hydrophilic and is defined by the side chains of Y7, F8, V10, R13, V104, Y108, N204, and G205 and five water molecules. A hydrogen bond network connects the five water molecules and the side chains of R13 and N204. V104 is positioned such that the introduction of a methyl group (the result of the V104I mutation) disturbs the H-site water structure and alters the substrate-binding properties of the isozyme. The hydroxyl group of Y7 forms a hydrogen bond (3.2 A) with the sulfur atom of the product. There is a short hydrogen bond (2.5 A) between Y108 (OH) and (9R, 10R)-GSPhen (O5), indicating the hydroxyl group of Y108 as an electrophilic participant in the addition of glutathione to epoxides. An N-(2-hydroxethyl)piperazine-N'-2-ethanesulfonic acid (HEPES) molecule is found in the cavity between beta2 and alphaI. The location and properties of this HEPES-binding site fit a possible non-substrate-binding site that is involved in noncompetitive inhibition of the enzyme.

Animals↗
PubMed2005

Water mediated proton transfer in a mesostructured aluminosilicate framework: an ab initio molecular dynamics study.

The proton transfer process mediated by water molecules adsorbed in an aluminosilicate framework has been studied using ab initio molecular dynamics simulations. This investigation has been carried out using a quasi-one-dimensional model simulating the mesoporous aluminosilicate channel structures. The effects of both the water loading and temperature of the system have been considered. At low coverage (one water molecule per acid site), the hydroxonium ion (H(3)O)(+) is found to be a transition state, in agreement with earlier studies on zeolites. At a higher water coverage (two water molecules per acid site), the (H(5)O(2))(+) species and the hydrogen bonded "neutral complex" structure are both found to be stable complexes at finite temperatures. The vibrational frequency spectrum is simulated by performing a Fourier transform of the velocity autocorrelation function (VAF), and the peak positions in the VAF are compared with IR measurements and zero-temperature calculations.

Adsorption↗
PubMedDate not supplied

Imaging of chemiluminescent reactions in mesoscale silicon-glass microstructures.

Chemiluminescent reactions in mesoscale analytical structures (chips) containing micrometre-sized interconnecting channels and chambers (pL-nL total volume) were imaged. The chips were fabricated by bonding Pyrex glass to etched pieces of silicon using a high-temperature diffusive bonding technique. In initial experiments light emission from an enhanced chemiluminescent horseradish peroxidase reaction and from a peroxyoxalate reaction contained in straight channels (300 microns wide x 20 mu deep; volume 70.2 nL) and open chambers (812 microns wide, 400 microns deep, 5.2 mm long) linked by channels (100 microns wide, 20 microns deep) to an exit and entry port were studied using a specially modified microplate holder and an Amerlite microplate luminometer. Light emission from more complex structures (two chambers interconnected by a branching channel 100 microns wide, 20 microns deep) filled with a solution containing alkaline phosphatase, Emerald, and CSPD was imaged using a Photometrics Star 1 CCD camera. Detailed investigation of the detection and spatial resolution of the signal was performed on a Berthold Luminograph LB 980 using both the enhanced chemiluminescent horseradish peroxidase reaction and a peroxyoxalate reaction. We successfully resolved light emission from silicon structures with dimensions 100 microns wide and 20 microns deep. These simple silicon structures served as models for more complex designs that will be used for simultaneous multi-analyte assays in which an imaging system resolves and quantitates light emission from different locations on a silicon-glass analytical device.

Glass↗
PubMed1998

A sea urchin gene encoding dystrophin-related proteins.

The gene which is defective in Duchenne muscular dystrophy (DMD) is the largest known gene. The product of the gene in muscle, dystrophin, is a 427 kDa protein. The same gene encodes at least six additional products: two non-muscle dystrophin isoforms transcribed from promoters located in the 5'-end region of the gene and four smaller proteins transcribed from internal promoters located further downstream. Several other genes, encoding evolutionarily related proteins, have been identified. These include a structurally very similar gene in vertebrates encoding utrophin (DRP1), which is closely related to dystrophin, and a number of small and simple genes in vertebrates or invertebrates encoding proteins similar to some of the small products of the DMD gene. We have isolated a sea urchin gene showing very strong sequence and structural homology with the DMD and utrophin genes. Sequence and intron/exon structure similarities suggest that this gene is related to a precursor of both the DMD gene and the gene encoding utrophin. The sea urchin gene has the unique complex structure of the DMD gene. There is at least one, and possibly more, product(s) transcribed from internal promoters, as well as a large product of >300 kDa containing at least three of the four major domains of dystrophin. The small product seems to be evolutionarily related to Dp116, one of the small products of the human DMD gene. Partial characterization of this gene helped us to construct an evolutionary tree connecting the vertebrate dystrophin gene family with related genes in invertebrates. The constructed evolutionary tree also implies that the vertebrate small and simple structured gene encoding a Dp71-like protein, called DRP2 , evolved from the dystrophin/utrophin ancestral large and complex gene by a duplication of only a small part of the gene.

Amino Acid Sequence↗
PubMed1995

Structural determinants of the ligand-binding site of the human retinoic acid receptor alpha.

The ligand-dependent transactivating properties of retinoic acid receptors are controlled through a complex structure at the C-terminus of these proteins, commonly referred to as the hormone binding domain. This domain is involved not only in ligand recognition but also in protein-protein interactions such as homo- and heterodimerization processes. To identify more precisely regions of the human all-trans-retinoic acid receptor alpha (hRAR alpha) that are involved in ligand binding, we constructed a series of deletion mutants of this molecule and overexpressed them in bacteria. We found that the C-terminal part of the D domain (amino acids 186-198) was necessary for ligand binding. The F domain and the 10 C-terminal amino acids of the E domain were dispensable for high-affinity binding of various natural and synthetic retinoids. A further deletion to position 403 resulted in a moderate decrease in affinity for all-trans-(ATRA) and 9-cis-retinoic acids, whereas the binding of two RAR alpha-specific ligands (Am80 and Am580) was abolished. In addition, hRAR alpha and the minimal hormone binding domain (amino acids 186-410) bound ATRA with a positive, cooperative mechanism. This behavior was not observed with CD367, a conformationally restricted synthetic retinoid. The positive cooperativity could be correlated with stable ATRA binding to RAR homodimers, whose formation was triggered by ligand. In the same conditions, only monomeric CD367-RAR alpha complexes were detected. These data indicate that ligand binding to hRAR alpha requires the presence of part of the D domain, whereas the C-terminal end of the E domain is involved in more subtle ligand recognition processes.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acid Sequence↗
PubMed2006

Characterization of sulfated oligosaccharides in mucopolysaccharidosis type IIIA by electrospray ionization mass spectrometry.

Heparan sulfate is a linear glycosaminoglycan with considerable structural diversity that binds a myriad of growth factors and proteins that play pivotal roles in a variety of biological processes. We have investigated the structural complexity of partially degraded fragments of heparan sulfate in mucopolysaccharidosis type IIIA in which there is a defect in heparan sulfate catabolism. Mono- to hexadecasaccharides were isolated from the urine of a mucopolysaccharidosis IIIA patient and shown to have non-reducing end glucosamine N-sulfate residues, reflecting the catabolic deficiency in heparan N-sulfatase (sulfamidase) activity. The use of nitrous acid digestion (pH 1.5) combined with separation by reverse-phase high-performance liquid chromatography and analysis by electrospray ionization-mass spectrometry identified multiple forms of these oligosaccharides with some N-acetylated glucosamine residues and one to three sulfates per disaccharide. Furthermore, we demonstrated that each oligosaccharide existed in multiple sulfated forms. Many structural isomers were present, suggesting a complex mixture of oligosaccharides present in the urine as a consequence of a defect in heparan sulfate degradation.

Animals↗