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The effects of alpha-helix on the stability of Asn residues: deamidation rates in peptides of varying helicity
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Kosky AA Razzaq UO Treuheit MJ Brems DN 《Protein science : a publication of the Protein Society》1999,8(11):2519-2523
Asn deamidation was monitored in Ala-based octadecapeptides of varying alpha-helicity. Gly was substituted for Ala residues at positions 6 and 16 to create a peptide with less helicity. Ala --> Gly substitutions were made at three or more residues from the Asn to negate known primary sequence effects on deamidation rates. The extent of helicity and rate of Asn deamidation for alkaline aqueous solutions of each peptide was measured as a function of temperature by circular dichroism and reversed-phase high-performance liquid chromatography, respectively. The rate of deamidation in the peptides was inversely proportional to the extent of alpha-helicity. The results support the conclusion that Asn deamidation only occurs in the nonhelical population of conformers. 相似文献
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J. L. Williams S. Dunner A. Valentini R. Mazza V. Amarger M. L. Checa A. Crisà N. Razzaq D. Delourme F. Grandjean C. Marchitelli D. García R. Pérez Gomez R. Negrini P. Ajmone Marsan H. Levéziel 《Animal genetics》2009,40(4):486-491
A large number of putative single nucleotide polymorphisms (SNPs) have been identified from the bovine genome-sequencing project. However, few of these have been validated and many will turn out to be sequencing artefacts or have low minor allele frequencies. In addition, there is little information available on SNPs within coding regions, which are likely to be responsible for phenotypic variation. Therefore, additional SNP discovery is necessary to identify and validate polymorphisms both in specific genes and genome-wide. Sequence-tagged sites within 286 genes were resequenced from a panel of animals representing a wide range of European cattle breeds. For 80 genes, no polymorphisms were identified, and 672 putative SNPs were identified within 206 genes. Fifteen European cattle breeds (436 individuals plus available parents) were genotyped with these putative SNPs, and 389 SNPs were confirmed to have minor allele frequencies above 10%. The genes containing SNPs were localized on chromosomes by radiation hybrid mapping and on the bovine genome sequence by Blast . Flanking microsatellite loci were identified, to facilitate the alignment of the genes containing the SNPs in relation to mapped quantitative trait loci. Of the 672 putative SNPs discovered in this work, only 11 were found among the validated SNPs and 100 were found among the approximately 2.3 million putative SNPs currently in dbSNP. The genes studied in this work could be considered as candidates for traits associated with beef production and the SNPs reported will help to assess the role of the genes in the genetic control of muscle development and meat quality. The allele frequency data presented allows the general utility of the SNPs to be assessed. 相似文献
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Shama Razzaq Asaad Ahmed Nafees Unaib Rabbani Muhammad Irfan Shahla Naeem Muhammad Arslan Khan Zafar Fatmi Peter Burney 《BMC pulmonary medicine》2018,18(1):184
Background
This study was conducted in order to determine the prevalence of asthma and associated risk factors in the adult population of Karachi, Pakistan.Methods
This multi-stage, cross-sectional survey was conducted from May 2014–August 2015; comprising 1629 adults in 75 randomly selected clusters in Karachi, Pakistan. Definitions included: ‘self-reported asthma’, ‘reversibility in FEV1’ and ‘respiratory symptoms and reversibility in FEV1’.Results
Prevalence of asthma was 1.8% (self-reported) (95% CI: 1.0–2.6), 11.3% (reversibility in FEV1) (95% CI: 9.4–13.3) and 6.6% (symptoms and reversibility in FEV1) (95% CI: 5.1–8.1). Asthmatics were more likely to belong to the age group ≥38?years according to ‘reversibility in FEV1’ and ‘respiratory symptoms and reversibility in FEV1’ (AOR: 1.9, 95% CI: 1.2–3.3) and (AOR: 2.1, 95% CI: 1.1–4.2), respectively. Asthmatics were more likely to report history of allergies (AOR: 1.9, 95% CI: 1.2–2.9) and (AOR: 2.8, 95% CI: 1.7–4.8); and were exposed to environmental tobacco smoke (AOR: 1.6, 95% CI: 1.1–2.5) and (AOR: 1.9, 95% CI: 1.1–3.3) according to ‘reversibility in FEV1’ and ‘respiratory symptoms and reversibility in FEV1’, respectively. Asthmatics were more likely to report pack years of smoking ≥5 (AOR: 2.3, 95% CI: 1.1–4.7) according to ‘respiratory symptoms and reversibility in FEV1’.Conclusion
This study reports a high prevalence of asthma among Pakistani adults and calls for developing appropriate public health policies for prevention and control of asthma in the country. Further studies should be conducted to determine the national prevalence as well as follow-up studies to identify preventable causes for adult asthma.45.
Ujala Sehar Muhammad Aamer Mehmood Salman Nawaz Shahid Nadeem Khadim Hussain Iqra Sohail Muhammad Rizwan Tabassum Saba Shahid Gill Anam Saqib 《Bioinformation》2013,9(14):725-729
Bacillus thuringiensis is an insecticidal bacterium whose chitinolytic system has been exploited to improve insect resistance in crops.
In the present study, we studied the CBP24 from B. thuringiensis using homology modeling and molecular docking. The primary
and secondary structure analyses showed CBP24 is a positively charged protein and contains single domain that belongs to family
CBM33. The 3D model after refinement was used to explore the chitin binding characteristics of CBP24 using AUTODOCK. The
docking analyses have shown that the surface exposed hydrophilic amino acid residues Thr-103, Lys-112 and Ser-162 interact with
substrate through H-bonding. While, the amino acids resides Glu-39, Tyr-46, Ser-104 and Asn-109 were shown to have polar
interactions with the substrate. The binding energy values evaluation of docking depicts a stable intermolecular conformation of
the docked complex. The functional characterization of the CBP24 will elucidate the substrate-interaction pathway of the protein in
specific and the carbohydrate binding proteins in general leading towards the exploration and exploitation of the prokaryotic
substrate utilization pathways. 相似文献
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Ujala Sehar Muhammad Aamer Mehmood Khadim Hussain Salman Nawaz Shahid Nadeem Muhammad Hussnain Siddique Habibullah Nadeem Munazza Gull Niaz Ahmad Iqra Sohail Saba Shahid Gill Summera Majeed 《Bioinformation》2013,9(18):901-907
This paper presents an in silico characterization of the chitin binding protein CBP50 from B. thuringiensis serovar konkukian S4
through homology modeling and molecular docking. The CBP50 has shown a modular structure containing an N-terminal
CBM33 domain, two consecutive fibronectin-III (Fn-III) like domains and a C-terminal CBM5 domain. The protein presented a
unique modular structure which could not be modeled using ordinary procedures. So, domain wise modeling using
MODELLER and docking analyses using Autodock Vina were performed. The best conformation for each domain was selected
using standard procedure. It was revealed that four amino acid residues Glu-71, Ser-74, Glu-76 and Gln-90 from N-terminal
domain are involved in protein-substrate interaction. Similarly, amino acid residues Trp-20, Asn-21, Ser-23 and Val-30 of Fn-III
like domains and Glu-15, Ala-17, Ser-18 and Leu-35 of C-terminal domain were involved in substrate binding. Site-directed
mutagenesis of these proposed amino acid residues in future will elucidate the key amino acids involved in chitin binding
activity of CBP50 protein. 相似文献
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A Razzaq S Schmitz C Veigel J E Molloy M A Geeves J C Sparrow 《The Journal of biological chemistry》1999,274(40):28321-28328
Many mutants have been described that affect the function of the actin encoded by the Drosophila melanogaster indirect flight muscle-specific actin gene, Act88F. We describe the development of procedures for purification of this actin from the other isoforms expressed in the fly as well as in vitro motility, single molecule force/displacement measurements, and stop-flow solution kinetic studies of the wild-type actin and that of the E93K mutation of the Act88F gene. We show that this mutation affects in vitro motility of F-actin, in both the presence and absence of methylcellulose, and the ability of the ACT88F actin to bind the S1 fragment of rabbit skeletal myosin. However, optical tweezer measurements of the actomyosin working stroke and the force transmitted from the rabbit heavy meromyosin to and through F-actin are unchanged by the mutation. These results support the proposal (Holmes, K. C. (1995) Biophys J. 68, (suppl.) 2-7) that actin residue Glu(93) is part of the secondary myosin binding site and suggest that myosin binding occurs first at the primary myosin binding site and then at the secondary site. 相似文献
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Biology Bulletin - As part of comprehensive study of lichen diversity of northern areas of Pakistan using molecular and morphological approaches, we found four species of the family Graphidaceae.... 相似文献