Search results for "proline"
showing 10 items of 183 documents
Collagen metabolism of mouse skeletal muscle during the repair of exercise injuries.
1986
The activities of prolyl 4-hydroxylase and beta-glucuronidase, the concentration of hydroxyproline as well as reticulin and collagen type III, IV and V stainings were followed in skeletal muscle during a 20-day period after a 9-h treadmill running in untrained and trained male mice, aged 4-6 months. The prolonged 9-h running of untrained mice temporarily increased prolyl 4-hydroxylase activity 2, 5 and 10 days after exercise, more prominently in the red than in the white part of quadriceps femoris-muscle, and in analogical manner as beta-glucuronidase activity in tibialis anterior-muscle. Twenty days after exercise these enzymatic activities were back to the control level. The hydroxyprolin…
Cecal Resection with Bipolar Sealing Devices in a Rat Model
2018
Background: Bipolar sealing devices are routinely used to seal blood vessels. The aim of the study is to evaluate the feasibility and safety of colonic sealing with the use of the bipolar energy devices in rats as model for experimental appendectomy. Methods: Seventy-five male Wistar rats underwent a cecal resection with four different bipolar sealing devices or a linear stapler. The harvesting procedure was performed immediately or at postoperative day (POD) 7. The sealing front bursting pressure (BP) was measured in both groups. At POD7, the resection line was clinically examined and the hydroxyproline (HDP) levels were determined. Hematoxylin and Eosin (H&E) staining was used for histopa…
Effectiveness, safety/tolerability of OBV/PTV/r ± DSV in patients with HCV genotype 1 or 4 with/without HIV-1 co-infection, chronic kidney disease (C…
2019
Background and aims Limited data are available on the effectiveness and tolerability of direct-acting antivirals (DAAs) therapies in the real world for HCV-infected patients with comorbidities. This study aimed to describe the effectiveness of OBV/PTV/r +/- DSV (3D/2D regimen) with or without ribavirin (RBV) in HCV or HCV/HIV co-infected patients with GT1/GT4 and CKD (IIIb-V stages), including those under hemodialysis and peritoneal dialysis in routine clinical practice in Spain in 2015. Material and methods Non-interventional, retrospective, multicenter data collection study in 31 Spanish sites. Socio-demographic, clinical variables, study treatment characteristics, effectiveness and toler…
Effects of Ribavirin Dose Reduction vs Erythropoietin for Boceprevir-Related Anemia in Patients With Chronic Hepatitis C Virus Genotype 1 Infection—A…
2013
International audience; Background & AimsTreatment of hepatitis C virus (HCV) infection with boceprevir, peginterferon, and ribavirin can lead to anemia, which has been managed by reducing ribavirin dose and/or erythropoietin therapy. We assessed the effects of these anemia management strategies on rates of sustained virologic response (SVR) and safety.MethodsPatients (n = 687) received 4 weeks of peginterferon and ribavirin followed by 24 or 44 weeks of boceprevir (800 mg, 3 times each day) plus peginterferon and ribavirin. Patients who became anemic (levels of hemoglobin approximately ≤10 g/dL) during the study treatment period (n = 500) were assigned to groups that were managed by ribavi…
Copper(II)-Induced Restructuring of ZnuD, a Zinc(II) Transporter from Neisseria meningitidis.
2019
Cluster 2 (288HDDDNAHAHTH298) from Neisseria meningitidis ZnuD is a flexible loop that captures zinc(II) ions, acting as a "fishing net". We describe its Zn(II) and Cu(II) binding capabilities, focusing on the thermodynamics of such interactions and comparing them with the complexes of the 1MAHHHHHHL9-NH2 region. Copper(II) complexes with the studied ZnuD regions are thermodynamically more stable than the zinc(II) ones-Cu(II) complexes dominate in solution even in close to physiological ratios of the studied metal ions (a 10-fold excess of Zn(II) over Cu(II)). While the binding of native Zn(II) has no significant impact on the structure of its transporter, Cu(II) binding induces a conformat…
Conformational control of Bax localization and apoptotic activity by Pro168.
2004
In healthy cells, Bax resides inactive in the cytosol because its COOH-terminal transmembrane region (TMB) is tucked into a hydrophobic pocket. During apoptosis, Bax undergoes a conformational change involving NH2-terminal exposure and translocates to mitochondria to release apoptogenic factors. How this process is regulated remains unknown. We show that the TMB of Bax is both necessary and sufficient for mitochondrial targeting. However, its availability for targeting depends on Pro168 located within the preceding loop region. Pro168 mutants of Bax lack apoptotic activity, cannot rescue the apoptosis-resistant phenotype of Bax/Bak double knockout cells, and are retained in the cytosol even…
A Ser residue influences the structure and stability of a Pro-kinked transmembrane helix dimer
2012
AbstractWhen localized adjacent to a Pro-kink, Thr and Ser residues can form hydrogen bonds between their polar hydroxyl group and a backbone carbonyl oxygen and thereby modulate the actual bending angle of a distorted transmembrane α-helix. We have used the homo-dimeric transmembrane cytochrome b559′ to analyze the potential role of a highly conserved Ser residue for assembly and stabilization of transmembrane proteins. Mutation of the conserved Ser residue to Ala resulted in altered heme binding properties and in increased stability of the holo-protein, most likely by tolerating subtle structural rearrangements upon heme binding. The results suggest a crucial impact of an intrahelical Ser…
Influence of proline residues in transmembrane helix packing
2003
Integral membrane proteins often contain proline residues in their alpha-helical transmembrane (TM) fragments, which may strongly influence their folding and association. Pro-scanning mutagenesis of the helical domain of glycophorin A (GpA) showed that replacement of the residues located at the center abrogates helix packing while substitution of the residues forming the ending helical turns allows dimer formation. Synthetic TM peptides revealed that a point mutation of one of the residues of the dimerization motif (L75P) located at the N-terminal helical turn of the GpA TM fragment, adopts a secondary structure and oligomeric state similar to the wild-type sequence in detergents. In additi…
Structure of the altitude adapted hemoglobin of Guinea pig in the R2-state
2010
Background: Guinea pigs are considered to be genetically adapted to a high altitude environment based on the consistent finding of a high oxygen affinity of their blood. Methodology/Principal Findings: The crystal structure of guinea pig hemoglobin at 1.8 A u resolution suggests that the increased oxygen affinity of guinea pig hemoglobin can be explained by two factors, namely a decreased stability of the Tstate and an increased stability of the R2-state. The destabilization of the T-state can be related to the substitution of a highly conserved proline (P44) to histidine (H44) in the a-subunit, which causes a steric hindrance with H97 of the b-subunit in the switch region. The stabilizatio…
String kernels and high-quality data set for improved prediction of kinked helices in α-helical membrane proteins.
2011
The reasons for distortions from optimal α-helical geometry are widely unknown, but their influences on structural changes of proteins are significant. Hence, their prediction is a crucial problem in structural bioinformatics. For the particular case of kink prediction, we generated a data set of 132 membrane proteins containing 1014 manually labeled helices and examined the environment of kinks. Our sequence analysis confirms the great relevance of proline and reveals disproportionately high occurrences of glycine and serine at kink positions. The structural analysis shows significantly different solvent accessible surface area mean values for kinked and nonkinked helices. More important, …