Bremazocine Recognizes the Difference in Four Amino Acid Residues to Discriminate Between a Nociceptin/Orphanin FQ Receptor and Opioid Receptors

1. The content and distribution of carbohydrate was examined in mucus glycopolypeptides from human antral mucosae. 2. The mean amount of carbohydrate per 1000 amino acid residues was found to be similar in glycopolypeptides with A, B or H activity. It was slightly, though significantly, less in glycopolypeptides lacking these determinants, because carbohydrate chains were of a shorter average length than in the A-, B- or H-active preparations. This difference was reflected in the sizes of oligosaccharide—alcohols released from representative glycopolypeptides with alkaline borohydride. 3. Differences between A-, B- or H-active and non-secretor glycopolypeptides in terms of the mean number of carbohydrate chains per 1000 amino acid residues were found to be small, and without significance. 4. The average number of peripheral monosaccharide units per 1000 amino acid residues was greater in A-active than in H-active, and least in non-secretor, glycopolypeptides. This order was reversed for monosaccharide units incorporated into skeletal (core plus backbone) structures. The difference in each case was statistically significant. 5. These findings suggest that the increased risk of peptic ulcer associated with blood group O and non-secretor status is unlikely to be attributable to an inherent deficiency in the protective mucus layer, linked to differences between mucins that are associated with A, B or H activity. Other hypotheses linked to infection with Helicobacter pylori are examined.

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Comparison of the Amino Acid Residues in the Sixth Transmembrane Domains Accessible in the Binding-Site Crevices of μ, δ, and κ Opioid Receptors†

Biochemistry ◽

10.1021/bi002490d ◽

2001 ◽

Vol 40 (27) ◽

pp. 8018-8029 ◽

Cited By ~ 17

Author(s):

Wei Xu ◽

Jin Li ◽

Chongguang Chen ◽

Peng Huang ◽

Harel Weinstein ◽

...

Keyword(s):

Amino Acid ◽

Binding Site ◽

Opioid Receptors ◽

Transmembrane Domains ◽

Amino Acid Residues

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Studies on Chymotrypsin-P. I. Characterization

Canadian Journal of Biochemistry ◽

10.1139/o71-146 ◽

1971 ◽

Vol 49 (9) ◽

pp. 999-1004 ◽

Cited By ~ 2

Author(s):

M. C. Shaw ◽

T. Viswanatha

Keyword(s):

Molecular Weight ◽

Amino Acid ◽

Physicochemical Properties ◽

Gel Filtration ◽

Amino Acid Residues ◽

The Difference ◽

Filtration Technique

The physicochemical properties of chymotrypsin-P obtained by the papain activation of chymotrypsinogen have been investigated. The molecular weight of this enzyme as determined by gel filtration technique has been found to be 24 000 ± 1000. The amino acid residues occupying the N-terminal positions and the composition of the B- and C-chains of chymotrypsin-P are identical with those found in α-chymotrypsin. Thus the difference between the two enzymes is restricted to the composition of their A-chains.

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Determination of three amino acids causing alteration of proteolytic activities of staphylococcal glutamyl endopeptidases

Biological Chemistry ◽

10.1515/bc.2009.027 ◽

2009 ◽

Vol 390 (3) ◽

Cited By ~ 5

Author(s):

Takayuki K. Nemoto ◽

Toshio Ono ◽

Yu Shimoyama ◽

Shigenobu Kimura ◽

Yuko Ohara-Nemoto

Keyword(s):

Amino Acids ◽

Amino Acid ◽

Protease Activity ◽

Binding Pocket ◽

Catalytic Triad ◽

Amino Acid Residues ◽

Proteolytic Activities ◽

Hydrophobic Amino Acids ◽

The Difference

Abstract Staphylococcus aureus, Staphylococcus epidermidis, and Staphylococcus warneri secrete glutamyl endopeptidases, designated GluV8, GluSE, and GluSW, respectively. The order of their protease activities is GluSE<GluSW<<GluV8. In the present study, we investigated the mechanism that causes these differences. Expression of chimeric proteins between GluV8 and GluSE revealed that the difference is primarily attributed to amino acid residues 170–195, which define the intrinsic protease activity, and additionally to residues 119–169, which affect the proteolytic sensitivity. Among nine substitutions present in residues 170–195 of the three proteases, the substitutions at positions 185, 188, and 189 were responsible for the changes in their activities, and the combination of W185, V188, and P189, which naturally occurs in GluV8, exerts the highest protease activity. W185 and P189 were indispensable for full activity, but V188 could be replaced by hydrophobic amino acids. These three amino acid residues appear to create a substrate-binding pocket together with the catalytic triad and the N-terminal V1, and therefore define the K m values of the proteases. We also describe a method to produce a chimeric form of GluSE and GluV8 that is resistant to proteolysis, and therefore possesses 4-fold higher activity than the wild-type recombinant GluV8.

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The Acinetobacter baylyi hfq Gene Encodes a Large Protein with an Unusual C Terminus

Journal of Bacteriology ◽

10.1128/jb.00490-09 ◽

2009 ◽

Vol 191 (17) ◽

pp. 5553-5562 ◽

Cited By ~ 20

Author(s):

Dominik Schilling ◽

Ulrike Gerischer

Keyword(s):

Amino Acid ◽

Gene Localization ◽

Amino Acid Residues ◽

Acinetobacter Baylyi ◽

Reading Frame ◽

Rich Domain ◽

C Terminus ◽

The Difference ◽

Cell Phenotypes

ABSTRACT In gammaproteobacteria the Hfq protein shows a great variation in size, especially in its C-terminal part. Extremely large Hfq proteins consisting of almost 200 amino acid residues and more are found within the gammaproteobacterial family Moraxellaceae. The difference in size compared to other Hfq proteins is due to a glycine-rich domain near the C-terminal end of the protein. Acinetobacter baylyi, a nonpathogenic soil bacterium and member of the Moraxellaceae encodes a large 174-amino-acid Hfq homologue containing the unique and repetitive amino acid pattern GGGFGGQ within the glycine-rich domain. Despite the presence of the C-terminal extension, A. baylyi Hfq complemented an Escherichia coli hfq mutant in vivo. By using polyclonal anti-Hfq antibodies, we detected the large A. baylyi Hfq that corresponds to its annotated size indicating the expression and stability of the full protein. Deletion of the complete A. baylyi hfq open reading frame resulted in severe reduction of growth. In addition, a deletion or overexpression of Hfq was accompanied by the loss of cell chain assembly. The glycine-rich domain was not responsible for growth and cell phenotypes. hfq gene localization in A. baylyi is strictly conserved within the mutL-miaA-hfq operon, and we show that hfq expression starts within the preceding miaA gene or further upstream.

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Cloning of the obese gene (ob) of adipose tissue, and differences in ob gene expression with age of piglets

Chinese Journal of Agricultural Biotechnology ◽

10.1079/cjb200575 ◽

2005 ◽

Vol 2 (3) ◽

pp. 207-212

Author(s):

Wang Yi-Zhen ◽

Chu Xiao-Na ◽

Huang Hai-Qing ◽

Han Fei-Fei ◽

Liu Jian-Xin

Keyword(s):

Gene Expression ◽

Adipose Tissue ◽

Amino Acid ◽

Internal Control ◽

Mrna Levels ◽

Amino Acid Residues ◽

Rt Pcr ◽

Amino Acid Homology ◽

Pcr Product ◽

The Difference

AbstractGenomic RNA was extracted from the subcutaneous adipose tissue of piglets (Duroc×Landrace×Tai-hu) at 1, 14, 28, 42 and 56 days of age, and obese gene (ob) mRNA was amplified using reverse transcriptase-polymerase chain reaction (RT-PCR). A DNA fragment of about 504 bp was obtained and the PCR product was cloned into a pGEM-T vector. The ob gene was isolated and sequenced from the positive clones screened. Sequence analysis suggested that this fragment was a partial sequence of ob cDNA, coding 167 amino acid residues, which constituted the major part of leptin mature protein. The gene homology of the fragment obtained in this study compared to the reported ob cDNA sequence in adipocytes of pig was 99.405%, and amino acid homology was 98.94%. Based on the ob gene clone, we successfully constructed an optimal semi-quantitative RT-PCR method. Using β-actin as the internal control, we investigated the difference of ob gene expression at different ages of piglets. Results showed that ob mRNA levels increased steadily at postnatal days 1–28 (preweaning), peaked at postnatal day 28, when piglets were weaned, and decreased from day 28 to 56.

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Mink Subdomains That Mediate Modulation of and Association with Kvlqt1

The Journal of General Physiology ◽

10.1085/jgp.116.3.379 ◽

2000 ◽

Vol 116 (3) ◽

pp. 379-390 ◽

Cited By ~ 57

Author(s):

Andrew R. Tapper ◽

Alfred L. George

Keyword(s):

Amino Acid ◽

Potassium Current ◽

Transmembrane Domain ◽

Cardiac Cells ◽

Na Channel ◽

Amino Acid Residues ◽

Structural Determinants ◽

The Difference ◽

Heterologous Expression Systems ◽

Gating Modulation

KvLQT1 is a voltage-gated potassium channel expressed in cardiac cells that is critical for myocardial repolarization. When expressed alone in heterologous expression systems, KvLQT1 channels exhibit a rapidly activating potassium current that slowly deactivates. MinK, a 129 amino acid protein containing one transmembrane-spanning domain modulates KvLQT1, greatly slowing activation, increasing current amplitude, and removing inactivation. Using deletion and chimeric analysis, we have examined the structural determinants of MinK effects on gating modulation and subunit association. Coexpression of KvLQT1 with a MinK COOH-terminus deletion mutant (MinK ΔCterm) in Xenopus oocytes resulted in a rapidly activated potassium current closely resembling currents recorded from oocytes expressing KvLQT1 alone, indicating that this region is necessary for modulation. To determine whether MinK ΔCterm was associated with KvLQT1, a functional tag (G55C) that confers susceptibility to partial block by external cadmium was engineered into the transmembrane domain of MinK ΔCterm. Currents derived from coexpression of KvLQT1 with MinK ΔCterm were cadmium sensitive, suggesting that MinK ΔCterm does associate with KvLQT1, but does not modulate gating. To determine which MinK regions are sufficient for KvLQT1 association and modulation, chimeras were generated between MinK and the Na+ channel β1 subunit. Chimeras between MinK and β1 could only modulate KvLQT1 if they contained both the MinK transmembrane domain and COOH terminus, suggesting that the MinK COOH terminus alone is not sufficient for KvLQT1 modulation, and requires an additional, possibly associative interaction between the MinK transmembrane domain and KvLQT1. To identify the MinK subdomains necessary for gating modulation, deletion mutants were designed and coexpressed with KvLQT1. A MinK construct with amino acid residues 94–129 deleted retained the ability to modulate KvLQT1 gating, identifying the COOH-terminal region critical for gating modulation. Finally, MinK/MiRP1 (MinK related protein-1) chimeras were generated to investigate the difference between these two closely related subunits in their ability to modulate KvLQT1. The results from this analysis indicate that MiRP1 cannot modulate KvLQT1 due to differences within the transmembrane domain. Our results allow us to identify the MinK subdomains that mediate KvLQT1 association and modulation.

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Separate bisphosphatase domain of chicken liver 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase: the role of the C-terminal tail in modulating enzyme activity

Biochemical Journal ◽

10.1042/bj3280751 ◽

1997 ◽

Vol 328 (3) ◽

pp. 751-756 ◽

Cited By ~ 6

Author(s):

Lin LI ◽

Song LING ◽

Chun-lai WU ◽

Wei-zhe YAO ◽

Gen-jun XU

Keyword(s):

Enzyme Activity ◽

Amino Acid ◽

Substrate Inhibition ◽

Fold Increase ◽

Chicken Liver ◽

Bifunctional Enzyme ◽

Amino Acid Residues ◽

C Terminus ◽

Km Value ◽

The Difference

The separate bisphosphatase domain (amino acid residues 243-468) of the chicken liver bifunctional enzyme 6-phosphofructo-2-kinase-fructose-2,6-bisphosphatase was expressed in Escherichia coli and purified to homogeneity. The fructose-2,6-bisphosphatase activity of the separate domain was 7-fold higher than that of the native bifunctional enzyme, and exhibited substrate inhibition characteristic of the native enzyme. The inhibition of the enzymes by fructose 2,6-bisphosphate could be overcome by Pi, glycerol 3-phosphate and GTP. Deletion of 30 amino acid residues from the C-terminus of the separate domain resulted in around a 5-fold increase in the Vmax of the bisphosphatase. Also, the truncated form was more accessible to chemical modification by diethyl pyrocarbonate and N-ethylmaleimide, suggesting a more open structure than the wild-type form. In addition, the mutation of cysteine-389 to alanine increased bisphosphatase activity by 20% and the Km value for fructose 2,6-bisphosphate by 3-fold, and both the point mutation at cysteine-389 and the deletional mutation led to the predominantly insoluble expression of the enzyme. The results indicated that the C-terminal tail plays a role in modulating the enzyme activity and suggested that the difference in the C-terminal tail sequence is responsible for the difference in activity of the chicken and rat liver fructose-2,6-bisphosphatases. It is postulated that an interaction between the C-terminal tail and the active site might be present.

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Difference in susceptibility to CC chemokines among HIV 1 isolates

International Journal of STD & AIDS ◽

10.1258/0956462981922647 ◽

1998 ◽

Vol 9 (8) ◽

pp. 471-475 ◽

Cited By ~ 1

Author(s):

H Tsuchie ◽

T Q Jin ◽

J Zhang ◽

M A Detorio ◽

M M Hossain ◽

...

Keyword(s):

Amino Acid ◽

Chemokine Receptors ◽

Virus Entry ◽

Amino Acid Residues ◽

Cc Chemokine ◽

Cc Chemokines ◽

The Difference ◽

Anti Hiv ◽

Hiv 1 ◽

Positively Charged

In this study, we examined the difference in susceptibility to anti HIV activity of the CC chemokines RANTES, MIP 1 alpha and MIP 1 beta among HIV 1 isolates and analysed its relation with phenotype syncytium inducibility and V3 domain of gp120 of the HIV 1 isolates. Of 11 cases tested in endogenous assay, at a concentration of 200 ng ml, RANTES, MIP 1 alpha, and MIP 1 beta showed more than 80 suppression of HIV 1 replication in 10, 8, and 7 cases, respectively. HIV 1 isolates sensitive to more than one CC chemokine showed non syncytium inducing phenotype, whereas HIV 1 isolates resistant to all of the 3 CC chemokines showed syncytium inducing phenotype. HIV 1 isolates resistant to all of the 3 CC chemokines contained more positively charged amino acid residues in the V3 domain of the gp120. These results indicated that utilization of the CC chemokine receptors as co receptors for virus entry could vary among HIV 1 isolates.

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Identification of Amino Acid Residues in Human IgM Fc Receptor (FcµR) Critical for IgM Binding

Frontiers in Immunology ◽

10.3389/fimmu.2020.618327 ◽

2021 ◽

Vol 11 ◽

Author(s):

Christopher M. Skopnik ◽

Khlowd Al-Qaisi ◽

Rosaleen A. Calvert ◽

Philipp Enghard ◽

Andreas Radbruch ◽

...

Keyword(s):

Amino Acid ◽

Plasma Membranes ◽

Surface Expression ◽

Fc Receptor ◽

Receptor Expression ◽

Cell Surface Expression ◽

Binding Potential ◽

Amino Acid Residues ◽

Modeling Analysis ◽

The Difference

Both non-immune “natural” and antigen-induced “immune” IgM are important for protection against infections and for regulation of immune responses to self-antigens. The roles of its Fc receptor (FcµR) in these IgM effector functions have begun to be explored. In the present study, by taking advantage of the difference in IgM-ligand binding of FcµRs of human (constitutive binding) and mouse (transient binding), we replaced non-conserved amino acid residues of human FcµR with mouse equivalents before establishment of cell lines stably expressing mutant or wild-type (WT) receptors. The resultant eight-different mutant FcµR-bearing cells were compared with WT receptor-bearing cells for cell-surface expression and IgM-binding by flow cytometric assessments using receptor-specific mAbs and IgM paraproteins as ligands. Three sites Asn66, Lys79-Arg83, and Asn109, which are likely in the CDR2, DE loop and CDR3 of the human FcµR Ig-like domain, respectively, were responsible for constitutive IgM binding. Intriguingly, substitution of Glu41 and Met42 in the presumed CDR1 with the corresponding mouse residues Gln and Leu, either single or more prominently in combination, enhanced both the receptor expression and IgM binding. A four-aa stretch of Lys24-Gly27 in the predicted A ß-strand of human FcµR appeared to be essential for maintenance of its proper receptor conformation on plasma membranes because of reduction of both receptor expression and IgM-binding potential when these were mutated. Results from a computational structural modeling analysis were consistent with these mutational data and identified a possible mode of binding of FcµR with IgM involving the loops including Asn66, Arg83 and Asn109 of FcµR interacting principally with the Cµ4 domain including Gln510 and to a lesser extent Cµ3 domain including Glu398, of human IgM. To our knowledge, this is the first experimental report describing the identification of amino acid residues of human FcµR critical for binding to IgM Fc.

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