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1.
Int J STD AIDS ; 34(11): 763-776, 2023 10.
Artículo en Inglés | MEDLINE | ID: mdl-37269245

RESUMEN

Background: HIV pre-exposure prophylaxis (PrEP) is part of India's HIV prevention policy. We aimed to determine awareness of and willingness-to-use PrEP among men-who-have-sex-with-men (MSM) and transgender-persons (TG) in Delhi, India.Methods: A cross-sectional study was conducted at five purposively selected targeted-intervention projects in Delhi. Participants included self-identified MSM/TG aged ≥18 years, with negative/unknown HIV serostatus. A structured interview schedule, developed using formative research, was used. Primary outcomes were awareness of, and willingness-to-use PrEP. Socio-demographic and behaviour variables included age, living situation, education, anal-sex, condom-use and experiences of physical-violence. Determinants of outcome were identified in univariable logistic regression; variables associated at p < .25 were included in multivariable regression models.Results: Of 400 (224 MSM, 176 TG), mean ± SD age 25.7 ± 7.2 years, 14.5% (95% CI 11.0, 18.0) were aware of PrEP, while 63.3% (95% CI: 58.6, 68.1) reported willingness-to-use PrEP. PrEP-awareness was independently associated with formal-education (adjusted odds ratio; AOR = 1.20), professional occupation (AOR = 5.45) and condom-use (AOR = 3.07). Willingness-to-use PrEP was higher if participants had recent anal-sex (AOR = 2.29), had used condoms during anal-sex (AOR = 2.09), or recently experienced physical-violence (AOR = 3.65).Conclusions: PrEP awareness was low, but most were willing to use PrEP, implying that communication is key to PrEP awareness and uptake.


Asunto(s)
Infecciones por VIH , Profilaxis Pre-Exposición , Minorías Sexuales y de Género , Personas Transgénero , Masculino , Humanos , Adolescente , Adulto , Adulto Joven , Homosexualidad Masculina , Estudios Transversales , Infecciones por VIH/epidemiología , Infecciones por VIH/prevención & control , India/epidemiología
2.
AIDS Behav ; 27(9): 2875-2882, 2023 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-36750486

RESUMEN

The COVID-19 pandemic posed unprecedented challenges to HIV services globally. We evaluated the impact of the COVID-19 pandemic on the uptake of HIV testing in the Targeted Intervention (TI) program in Maharashtra-a high HIV burden state in India. Annual HIV testing was sustained during the pandemic year (2020-2021), at levels similar to the pre-pandemic year (2019-2020), among Female Sex Workers (FSW), Men having Sex with Men (MSM), Transgender (TG), and Truckers; but not among Migrants and Intravenous Drug Users (IDU). There was an acute decline during the lockdown across all typologies. Sharp recovery was seen among FSW, MSM, and TG during the early months of the un-lockdown. The community-based screening (CBS) approach primarily contributed to this recovery. Among migrants and truckers, recovery was delayed. There was an overall reduction of 58% in annual HIV-positive registrations. The community-based networks, participatory structures, and processes of HIV programs played an essential role in reaching the community during the pandemic.


Asunto(s)
COVID-19 , Infecciones por VIH , Trabajadores Sexuales , Minorías Sexuales y de Género , Masculino , Humanos , Femenino , Infecciones por VIH/diagnóstico , Infecciones por VIH/epidemiología , Infecciones por VIH/prevención & control , Homosexualidad Masculina , Pandemias/prevención & control , India/epidemiología , COVID-19/epidemiología , Control de Enfermedades Transmisibles , Prueba de VIH
3.
PLOS Glob Public Health ; 2(10): e0000437, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-36962491

RESUMEN

Transgender women globally are disproportionately burdened by HIV. Co-occurring epidemics of adverse psychosocial exposures accelerate HIV sexual risk, including among transgender women; however, studies using additive models fail to examine synergies among psychosocial conditions that define a syndemic. We examined the impact of synergistic interactions among 4 psychosocial exposures on condomless anal sex (CAS) among transgender women in India. A national probability-based sample of 4,607 HIV-negative transgender women completed the Indian Integrated Biological and Behavioural Surveillance survey, 2014-2015. We used linear probability regression and logistic regression to assess 2-, 3-, and 4-way interactions among 4 psychosocial exposures (physical violence, sexual violence, drug use, and alcohol use) on CAS. Overall, 27.3% reported physical and 22.3% sexual violence victimization (39.2% either physical or sexual violence), one-third (33.9%) reported frequent alcohol use and 11.5% illicit drug use. Physical violence was associated with twofold higher odds of CAS in the main effects model. Statistically significant two- and three-way interactions were identified, on both the multiplicative and the additive scales, between physical violence and drug use; physical and sexual violence; physical violence, sexual violence, and alcohol use; and physical violence, alcohol use and drug use. Physical and sexual violence victimization, and alcohol and drug use are highly prevalent and synergistically interact to increase CAS among HIV-negative transgender women in India. Targeted and integrated multilevel initiatives to improve the assessment of psychosocial comorbidities, to combat systemic transphobic violence, and to provide tailored, trauma-informed alcohol and substance use treatment services may reduce HIV risk among transgender women.

4.
Pharmacology ; 107(1-2): 54-68, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-34814141

RESUMEN

INTRODUCTION: The present study deals with the synthesis of pregnane-oximino-amino-alkyl-ethers and their evaluation for antidiabetic and anti-dyslipidemic activities in validated animal and cell culture models. METHODS: The effect on glucose tolerance was measured in sucrose-loaded rats; antidiabetic activity was evaluated in streptozotocin (STZ)-induced diabetic rats and genetically diabetic db/db mice; the anti-dyslipidemic effect was characterized in high-fructose, high-fat diet (HFD)-fed dyslipidemic hamsters. The effect on glucose production and glucose utilization was analyzed in HepG2 liver and L6 skeletal muscle cells, respectively. RESULTS: From the synthesized molecules, pregnane-oximino-amino-alkyl-ether (compound 14b) improved glucose clearance in sucrose-loaded rats and exerted antihyperglycemic activity on STZ-induced diabetic rats. Further evaluation in genetically diabetic db/db mice showed temporal decrease in blood glucose, and improvement in glucose tolerance and lipid parameters, associated with mild improvement in the serum insulin level. Moreover, compound 14b treatment displayed an anti-dyslipidemic effect characterized by significant improvement in altered lipid parameters of the high-fructose, HFD-fed dyslipidemic hamster model. In vitro analysis in the cellular system suggested that compound 14b decreased glucose production in liver cells and stimulated glucose utilization in skeletal muscle cells. These beneficial effects of compound 14b were associated with the activation of the G-protein-coupled bile acid receptor TGR5. CONCLUSION: Compound 14b exhibits antidiabetic and anti-dyslipidemic activities through activating the TGR5 receptor system and can be developed as a lead for the management of type II diabetes and related metabolic complications.


Asunto(s)
Diabetes Mellitus Experimental/tratamiento farmacológico , Dislipidemias/tratamiento farmacológico , Hipoglucemiantes/farmacología , Hipolipemiantes/farmacología , Pregnanos/farmacología , Receptores Acoplados a Proteínas G/agonistas , Animales , Glucemia/efectos de los fármacos , Línea Celular , Cricetinae , Diabetes Mellitus Experimental/metabolismo , Dislipidemias/metabolismo , Fenofibrato/farmacología , Fenofibrato/uso terapéutico , Transportador de Glucosa de Tipo 4/metabolismo , Humanos , Hipoglucemiantes/química , Hipoglucemiantes/farmacocinética , Hipoglucemiantes/uso terapéutico , Hipolipemiantes/química , Hipolipemiantes/farmacocinética , Hipolipemiantes/uso terapéutico , Masculino , Ratones , Músculo Esquelético/efectos de los fármacos , Pregnanos/química , Pregnanos/farmacocinética , Pregnanos/uso terapéutico , Ratas , Ratas Sprague-Dawley , Receptores Acoplados a Proteínas G/metabolismo
6.
Clin Chim Acta ; 411(7-8): 474-80, 2010 Apr 02.
Artículo en Inglés | MEDLINE | ID: mdl-20080081

RESUMEN

BACKGROUND: The genetic susceptibility to chronic obstructive pulmonary disease (COPD) depends on detoxification and antioxidant enzymes, which detoxify cigarette smoke reactive components that, otherwise, generate oxidative stress. METHODS: In a case-control study of 346 subjects with and without COPD, we examined the polymorphisms 462Ile/Val, 3801T/C of CYP1A1, -3860G/A of CYP1A2 and -930A/G, 242C/T of CYBA individually or in combination and their contribution to oxidative stress markers by measuring malondialdehyde (MDA), catalase (CAT), glutathione (GSH) and glutathione peroxidase (GPx). RESULTS: COPD patients had significantly increased MDA concentration (p<0.001) and decreased CAT activity, GSH concentration, GPx activity (p< or =0.01). The patients were over-represented by the alleles 462Val, 3801C of CYP1A1 and -930G, 242C of CYBA (p<0.001, p=0.003, p=0.030 and p=0.031, respectively) and consequently the haplotypes of same alleles i.e. 462Val:3801C, 462Val:3801T and -930G:242C (p=0.048, p=0.016 and p=0.039, respectively). Similarly, CYP1A1 and CYP1A2 haplotypes, 462Val:3860G and 462Val:3801T:3860G were significantly over-represented (p=0.001 and p=0.003), respectively in patients. The same alleles-associated genotype-combinations between genes were more prevalent in patients. Of note, the genotypes, 462Ile/Val+Val/Val, 3801TC+CC of CYP1A1 and -930AG+GG of CYBA associated with increased MDA concentration (p=0.018, p=0.045 and p=0.017, respectively), decreased CAT activity (p<0.0001, p=0.080 and p<0.0001, respectively) and GSH concentration (p<0.0001, p=0.0002 and p=0.011, respectively) in patients. CONCLUSION: The identified alleles, its haplotypes and the genotype-combination along with increased oxidative stress, signify the importance in susceptibility to COPD.


Asunto(s)
Citocromo P-450 CYP1A1/genética , Citocromo P-450 CYP1A2/genética , NADPH Oxidasas/genética , Estrés Oxidativo/genética , Polimorfismo Genético/genética , Enfermedad Pulmonar Obstructiva Crónica/genética , Adulto , Estudios de Casos y Controles , Femenino , Genotipo , Humanos , Masculino , Persona de Mediana Edad
7.
Indian J Pharm Sci ; 72(5): 607-12, 2010 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-21694993

RESUMEN

Thiazolidin-4-one fused pyrimidines, [1,5]-benzodiazepines and their oxygen substituted hydroxylamine derivatives have been screened for antibacterial, antifungal and antimalarial activity. Bacillus subtilis, Escherichia coli, Proteus mirabilis and Salmonella typhi were used for antibacterial screening. Aspergillus fumigatus and Candida albicans were used for antifungal screening and Plasmodium species were used for antimalarial screening. The antibacterial and antifungal activities are expressed in terms of zone of inhibition and antimalarial activity is expressed in IC(50) value. Fifteen compounds 2Xa, 2Xb, 2Xc, 2Xs, 3IV, 3Va, 3Vc, 3VIIIa, 3VIIIh, 3IXa, 3IXb, 3IXc, 3Xa, 4IXa and 4Xa were tested for antibacterial as well as antifungal activity and seven compounds 2IXb, 2Xb, 3VIIIc, 3Xc, 4IXa, 4Xa and 4IXw were tested for antimalarial activity. Streptomycin, griseofulvin and chloroquine were taken as standard drugs in antibacterial, antifungal and antimalarial activity, respectively. The compound 2Xs was found significant antimicrobial against Bacillus subtilis, E. coli, Aspergillus fumigatus and Candida albicans as well as compound 3Xa was significant antimicrobial against Bacillus subtilis, E. coli, Salmonella typhi, Aspergillus fumigatus and Candida albicans. The compound 2Xb showed significant antimalarial activity.

8.
Anal Biochem ; 387(2): 184-93, 2009 Apr 15.
Artículo en Inglés | MEDLINE | ID: mdl-19454248

RESUMEN

Depletion of high-abundance proteins is regarded as a critical sample preparation step for most plasma proteomic analyses and profiling strategies. This report describes a process that rapidly and reproducibly precipitates high-abundance disulfide-rich proteins, including albumin and transferrin, from serum and plasma. A low volume of concentrated reducing agent, viz. dithiothreitol (DTT) or tris(2-carboxyethyl)phosphine (TCEP), was added directly to plasma followed by a brief incubation at ambient temperature. Removal of the precipitate via centrifugation and identification of the protein content revealed an albumin-enriched pellet. Direct analysis of the supernatant by MALDI-TOF-MS afforded peptidome and small protein profiles with enhanced features and minimal ionization of full-length albumin. The reproducible and quantitative nature of the method has been demonstrated by monitoring the plasma levels of an antiangiogenic protein biologic, rKringle5 (rK5). The 10.5-kDa analyte was only reliably detected in plasma after treatment with reducing agent, ionizing linearly from 150 to 1200 fmol (on-target) with a mean CV of 7%. This method distinguishes itself from immunoaffinity resin-based approaches since it can be scaled to large milliliter quantities and it is compatible with plasma from all species tested.


Asunto(s)
Proteínas Sanguíneas/química , Animales , Precipitación Química , Haplorrinos , Humanos , Factor Plaquetario 4/sangre , Sustancias Reductoras/química , Espectrometría de Masa por Láser de Matriz Asistida de Ionización Desorción , Temperatura
9.
Clin Chim Acta ; 397(1-2): 48-50, 2008 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-18692035

RESUMEN

BACKGROUND: Cigarette smoke stimulates airway epithelial cells to release pro-inflammatory cytokines which influence various inflammation-related genes, including COX2, whereas p53 expression is known to alter in such a condition. Since both the genes share several common physiological functions including inflammation and oxidative stress, we investigated within gene and gene-gene interactions towards susceptibility to the disease. METHOD: In a prospective gene-association study we conducted PCR-RFLP for genotyping the COX2 -765G/C and 8473T/C and p53 72Pro/Arg polymorphisms in 229 COPD patients and 147 healthy controls. RESULTS: The -765GC+CC genotypes of COX2 and Pro/Pro+Pro/Arg genotypes of p53 were prevalent in patients with significant odds ratio, 2.05 and 2.30, respectively (p=0.001; p=0.009, respectively), as a consequence, the -765C and 72Pro alleles were prevalent (p

Asunto(s)
Ciclooxigenasa 2/genética , Predisposición Genética a la Enfermedad , Polimorfismo de Nucleótido Simple , Enfermedad Pulmonar Obstructiva Crónica/genética , Proteína p53 Supresora de Tumor/genética , Alelos , Frecuencia de los Genes , Genes p53 , Genotipo , Haplotipos , Humanos , India/epidemiología , Enfermedad Pulmonar Obstructiva Crónica/epidemiología
10.
Biochem Biophys Res Commun ; 361(1): 182-8, 2007 Sep 14.
Artículo en Inglés | MEDLINE | ID: mdl-17658478

RESUMEN

Nitric oxide (NO) plays critical role in endothelial dysfunction and oxidative stress in COPD, pointing to the significance of endothelial nitric oxide synthase gene (eNOS) variants. We investigated the association of -786T/C, -922A/G, 4B/4A, and 894G/T polymorphisms of eNOS with the disease and its impact on nitrite and malonaldehyde levels in 190 COPD patients and 134 healthy controls, all smokers. The -786C, -922G and 4A alleles were significantly over-represented in patients (p=0.02, p=0.02, and p=0.03, respectively). The haplotypes, -786C:4A, 4A:894G, -786C:894G, and -786C:4A:894G were significantly over-represented in patients (p<0.0001, p =0.02, p=0.02, and p <0.0001, respectively), whereas, haplotypes, -786T:4B, 4B:894G, -786T:894G, and -786T:4B:894G were significantly under-represented in the patients (p<0.0001). The patients had significantly increased levels of nitrite (p=0.003) and malonaldehyde (p<0.0001). Combination of genotypes containing -786C and 4A alleles were greater in patients (p 0.05), and these combinations associated with decreased FEV1 value and nitrite level (p=0.03 and p=0.04, respectively) and with increased malonaldehyde levels (p=0.02). The eNOS -786C, -922G, and 4A alleles, these alleles associated haplotypes and genotype combinations were over-represented in patients. The variants and their combinations of four polymorphisms of eNOS contribute to disturbed pulmonary function and oxidative stress in COPD.


Asunto(s)
Óxido Nítrico Sintasa de Tipo III/genética , Estrés Oxidativo/genética , Polimorfismo Genético , Enfermedad Pulmonar Obstructiva Crónica/genética , Adulto , Femenino , Frecuencia de los Genes , Ligamiento Genético , Genotipo , Haplotipos , Humanos , Masculino , Enfermedad Pulmonar Obstructiva Crónica/diagnóstico , Enfermedad Pulmonar Obstructiva Crónica/metabolismo
11.
Clin Biochem ; 40(13-14): 958-63, 2007 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-17631288

RESUMEN

OBJECTIVES: The imbalance in oxidative status together with nutrition depletion and low body weight play a vital role in the pathogenesis and severity of chronic obstructive pulmonary disease (COPD). The study was undertaken to ascertain if a relationship existed between oxidative status and BMI in COPD. In addition, association of oxidative status and BMI with lung function of the disease was also examined. MATERIALS AND METHODS: In 202 COPD patients and 136 healthy controls plasma lipid peroxidation (LPO), reduced glutathione (GSH), glutathione peroxidase (GPx), catalase (CAT) activities, BMI and FEV(1)% predicted were looked for interactions. RESULTS: The patients had increased LPO (p=0.006) and decreased antioxidants (GSH, p=0.005; GPx, p=0.035 and CAT, p=0.008, respectively). Of note are the correlations of oxidative stress markers with BMI and FEV(1)% predicted in the patients. LPO inversely and GSH, GPx, and CAT positively correlated with both BMI (p=0.007, p<0.001, p=0.045 and p=0.009, respectively), and FEV(1)% of predicted (LPO, p=0.001; GSH, p<0.001; GPx, p=0.043 and CAT, p<0.001) in the patients. Further, a positive correlation existed between BMI and FEV(1)% predicted (p=0.016) in COPD. CONCLUSION: The intimate relationship of oxidative status with BMI and lung function, and the direct correlation between BMI and FEV(1) may potentiate severity of the disease.


Asunto(s)
Índice de Masa Corporal , Estrés Oxidativo , Enfermedad Pulmonar Obstructiva Crónica/patología , Adulto , Antioxidantes/metabolismo , Femenino , Glutatión/sangre , Glutatión Peroxidasa/sangre , Humanos , Peroxidación de Lípido , Pulmón/metabolismo , Pulmón/patología , Pulmón/fisiopatología , Masculino , Persona de Mediana Edad , Enfermedad Pulmonar Obstructiva Crónica/sangre , Enfermedad Pulmonar Obstructiva Crónica/fisiopatología , Pruebas de Función Respiratoria
12.
Biochem Biophys Res Commun ; 359(1): 136-42, 2007 Jul 20.
Artículo en Inglés | MEDLINE | ID: mdl-17532303

RESUMEN

The genetic susceptibility to COPD might depend on variations in detoxification enzymes that activate and detoxify cigarette smoke products, which otherwise generate oxidative stress causing pathogenesis. In a case-control study of 202 COPD patients and 136 normals, we examined the association of polymorphisms I105V, A114V of GSTP1 and Y113H, H139R of mEPHX individually or in combination with disease and their contribution to oxidative stress markers such as MDA, GSH, GPx and airflow obstruction. Patients were over-represented by the alleles 105V, 114V of GSTP1 and 113H, 139H of mEPHX (chi(2)=10.63, p=0.001, chi(2)=13.92, p<0.001, chi(2)=13.02, p<0.001 and chi(2)=4.48, p=0.034, respectively) and the haplotypes of same alleles i.e. 105V-114V and 113H-139H (chi(2)=14.58, p<0.001 and chi(2)=23.14, p<0.001). Moreover, there was marked over-representation of combination of genotypes, I105I+A114A of GSTP1 (53% vs. 36%) in controls; whereas, the combinations with 105V/114V alleles (64% vs. 47%) of GSTP1 (OR=1.99; 95% CI=1.28-3.09; p=0.002) and the homozygotes H113H+H139H (27% vs.10%) of mEPHX (OR=3.26; 95% CI=1.73-6.15; p=0.0001) in patients. Patients had significantly elevated MDA level (p<0.001) and decreased GSH level (p<0.001) and GPx activity (p=0.035), respectively. Of note, the genotypes, I105V/V105V, A114V/V114V of GSTP1 and Y113H/H113H of mEPHX associated with increased MDA level (p=0.04, p=0.03 and p=0.003), decreased GSH level (p=0.019, p=0.007 and p=0.0006) and lower FEV1 (p=0.23, p=0.037 and p=0.029), respectively, in patients; so was the correlation of these biomarkers and lung function with the combinations of the genotypes. In conclusion, 105V/114V alleles of GSTP1 and 113H/139H alleles of mEPHX and the combination of genotypes with same alleles associated with imbalanced oxidative stress and lung function in patients, signifying the importance in the disease.


Asunto(s)
Epóxido Hidrolasas/genética , Gutatión-S-Transferasa pi/genética , Polimorfismo de Nucleótido Simple/genética , Enfermedad Pulmonar Obstructiva Crónica/diagnóstico , Enfermedad Pulmonar Obstructiva Crónica/genética , Especies Reactivas de Oxígeno/metabolismo , Adulto , Anciano , Anciano de 80 o más Años , Biomarcadores/metabolismo , Femenino , Predisposición Genética a la Enfermedad/genética , Humanos , Masculino , Persona de Mediana Edad , Estrés Oxidativo/genética , Pruebas de Función Respiratoria
13.
Clin Chim Acta ; 382(1-2): 37-42, 2007 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-17442289

RESUMEN

BACKGROUND: Detoxification genes are potential candidates in the susceptibility of patients with chronic obstructive pulmonary disease. Polymorphisms in these genes alter the metabolism of xenobiotics such as present in cigarette smoke. METHODS: We conducted a case-control study to investigate total 9 polymorphisms of CYP2E1, CYP2D6 and NAT2 genes by PCR-RFLP. RESULTS: The -1053C/T and -1293G/C promoter polymorphisms of CYP2E1 were found to be in complete linkage disequilibrium (LD) (D'=1.00, r(2)=1.0, p<0.0001), whereas -1293G/C and 7632T/A polymorphisms of the same gene were also in significant LD (D'=0.5183, r(2)=1.0, p=0.01) in patients. The patients over-represented the -1293GC+CC genotypes of -1293G/C polymorphism of CYP2E1 (p=0.03) and NAT2*4/7, NAT2()5/6, NAT2*5/7, NAT2*6/6 and NAT2*6/7 genotypes of NAT2 (p=0.01, p=0.039, p=0.01, p=0.032, p=0.006, respectively), resulting in to higher frequency of -1293C (OR=7.02, 95% CI=1.63-30.15, p=0.002), NAT2*6 (OR=1.90, 95% CI=1.27-2.83, p=0.001) and NAT2*7 (OR=2.91, 95% CI=1.65-5.12, p=0.0001) alleles. The 7632T/A and 9893C/G polymorphisms of CYP2E1 and 1934G/A polymorphism of CYP2D6 did not associate with the disease (p>0.05). The haplotypes -1293G:9893C and -1293G:7632T:9893C were under-represented (p<0.001), whereas haplotypes -1293C:7632T, -1293C:9893C, -1293C:9893G and -1293C:7632T:9893C of the 4 CYP2E1 polymorphisms were over-represented in patients (p<0.05). CONCLUSION: The CYP2E1 and NAT2 variants associated with COPD.


Asunto(s)
Arilamina N-Acetiltransferasa/genética , Citocromo P-450 CYP2E1/genética , Predisposición Genética a la Enfermedad/genética , Polimorfismo de Nucleótido Simple/genética , Enfermedad Pulmonar Obstructiva Crónica/genética , Anciano , Estudios de Casos y Controles , Femenino , Genotipo , Humanos , India , Masculino , Persona de Mediana Edad
14.
J Biol Chem ; 278(1): 71-5, 2003 Jan 03.
Artículo en Inglés | MEDLINE | ID: mdl-12414806

RESUMEN

PAPS synthetase (SK) catalyzes the two sequential reactions of phosphoadenosine phosphosulfate (PAPS) synthesis. A functional motif in the kinase domain of mouse SK, designated the BM-motif ((86) LDGDNhRxhh(N/S)(K/R)(97)), was defined in the course of identifying the brachymorphic (bm) defect. Sequence comparison and the secondary structure predicted for APS kinase suggest that the BM-motif consists of a DGD-turn sequence flanked by other conserved residues. Mutational analysis of the DGD-turn revealed that a flexible and neutral amino acid is preferred at residue 88, that negatively charged residues are strictly required at positions 87 and 89, and that the active site is rigid. The reduction in kinase activity for all DGD-turn mutants, except G88A, was much less severe than the reduction in overall activity, indicating that the BM-motif may also be playing a role in adenosine phosphosulfate (APS) channeling. Two switch mutations, LD86DL and DN89ND, designed to test the positional constraints of Asp(87) and Asp(89), exhibited complete loss of both kinase and overall activities, while LD86DL also exhibited a significant (60%) loss of reverse sulfurylase activity, suggesting that this peptide region is interacting with the sulfurylase domain as well as functioning in the kinase reaction. Other residues targeted for mutational analysis were the highly conserved flanking Asn(90), Arg(92), and Lys(97). N90A resulted in a partial (30%) loss in kinase and overall activities, R92A exhibited total loss of kinase and overall activities, and K97A had no effect on any of the three activities. The complexity of the bifunctional SK in catalyzing the kinase reaction and channeling APS is illustrated by the strict requirements of this novel structural motif in the kinase active site.


Asunto(s)
Complejos Multienzimáticos/química , Complejos Multienzimáticos/metabolismo , Conformación Proteica , Sulfato Adenililtransferasa/química , Sulfato Adenililtransferasa/metabolismo , Secuencias de Aminoácidos , Secuencia de Aminoácidos , Animales , Sitios de Unión , Humanos , Isoenzimas/genética , Isoenzimas/metabolismo , Ratones , Datos de Secuencia Molecular , Complejos Multienzimáticos/genética , Mutagénesis Sitio-Dirigida , Unión Proteica , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Alineación de Secuencia , Sulfato Adenililtransferasa/genética , Triptófano/metabolismo
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