Additive Structures
Mostrando 25-36 de 46 artigos, teses e dissertações.
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25. Potential use of additivity of mutational effects in simplifying protein engineering.
The problem of rationally engineering protein molecules can be simplified where effects of mutations on protein function are additive. Crystal structures of single and double mutants in the hydrophobic core of gene V protein indicate that structural and functional effects of core mutations are additive when the regions structurally influenced by the mutation
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26. An iterative method for extracting energy-like quantities from protein structures.
We present a method (ENERGI) for extracting energy-like quantities from a data base of protein structures. In this paper, we use the method to generate pairwise additive amino acid "energy" scores. These scores are obtained by iteration until they correctly discriminate a set of known protein folds from decoy conformations. The method succeeds in lattice mod
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27. Analysis of the Covariance Structure of Digital Ridge Counts in the Offspring of Monozygotic Twins
Improved methods for analysis of covariance structures now permit the rigorous testing of multivariate genetic hypotheses. Using Jöreskog 's Lisrel IV computer program we have conducted a confirmatory factor analysis of dermal ridge counts on the individual fingers of 509 offspring of 107 monozygotic twin pairs. Prior to the initiation of the model-fitting
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28. Should Individual Fitness Increase with Heterozygosity?
Natural selection influences not only gamete frequencies in populations but also the multilocus fitness structures associated with segregating gametes. In particular, only certain patterns of multilocus fitnesses are consistent with the maintenance of stable multilocus polymorphisms. This paper offers support for the proposition that, at stable, viability-ma
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29. Complementary molecular shapes and additivity of the packing parameter of lipids.
Physical dimensions of a membrane component influence its phase preference upon hydration. A dimensionless packing parameter, S, given by S = V/al, where V is the hydrocarbon volume, a is the area of the head group, and l is the critical length of the hydrocarbon chain, is useful in determining the phase preference of a lipid, and the value of S usually lies
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30. Methodology and Accuracy of Estimation of Quantitative Trait Loci Parameters in a Half-Sib Design Using Maximum Likelihood
Maximum likelihood methods were developed for estimation of the six parameters relating to a marker-linked quantitative trait locus (QTL) segregating in a half-sib design, namely the QTL additive effect, the QTL dominance effect, the population mean, recombination between the marker and the QTL, the population frequency of the QTL alleles, and the within-fam
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31. Approximate protein structural alignment in polynomial time
Alignment of protein structures is a fundamental task in computational molecular biology. Good structural alignments can help detect distant evolutionary relationships that are hard or impossible to discern from protein sequences alone. Here, we study the structural alignment problem as a family of optimization problems and develop an approximate polynomial-
National Academy of Sciences.
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32. Insight into the PrPC → PrPSc conversion from the structures of antibody-bound ovine prion scrapie-susceptibility variants
Prion diseases are associated with the conversion of the α-helix rich prion protein (PrPC) into a β-structure-rich insoluble conformer (PrPSc) that is thought to be infectious. The mechanism for the PrPC → PrPSc conversion and its relationship with the pathological effects of prion diseases are poorly understood, partly because of our limited knowledge o
National Academy of Sciences.
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33. Multiple AGAMOUS homologs from cucumber and petunia differ in their ability to induce reproductive organ fate.
The C function in Arabidopsis, which specifies stamen and carpel identity, is represented by a single gene called AGAMOUS (AG). From both petunia and cucumber, two MADS box genes have been isolated. Both share a high degree of amino acid sequence identity with the Arabidopsis AG protein. Their roles in specifying stamen and carpel identity have been studied
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34. Studies using double mutants of the conformational transitions in influenza hemagglutinin required for its membrane fusion activity
Amino acid substitutions widely distributed throughout the influenza hemagglutinin (HA) influence the pH of its membrane fusion activity. We have combined a number of these substitutions in double mutants and determined the effects on the pH of fusion and on the pH at which the refolding of HA required for fusion occurs. By analyzing combinations of mut
The National Academy of Sciences of the USA.
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35. The cationic porphyrin TMPyP4 destabilizes the tetraplex form of the fragile X syndrome expanded sequence d(CGG)n
Fragile X syndrome, the most common cause of inherited mental retardation, is instigated by dynamic expansion of a d(CGG) trinucleotide repeat in the 5′-untranslated region of the first exon of the FMR1 gene, resulting in its silencing. The expanded d(CGG)n tract readily folds into hairpin and tetraplex structures which may contribute to the blocking of FM
Oxford University Press.
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36. The hepatitis B virus post-transcriptional regulatory element contains two conserved RNA stem-loops which are required for function.
Human Hepatitis B Virus (HBV) RNAs contain a cis -acting sequence, the post-transcriptional regulatory element (HPRE), which facilitates the cytoplasmic localization of intronless transcripts. Our previous studies have shown that the HPRE is composed of at least two independent sub-elements, HPREalpha and HPREbeta, which co-activate a reporter for RNA export