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  • 1
    Electronic Resource
    Electronic Resource
    Variability of biochemical and clinical phenotype in X-linked liver glycogenosis with mutations in the phosphorylase kinase PHKA2 gene (1998)
    Springer
    Human genetics 〈Berlin〉 102 (1998), S. 423-429 
    Details
    ISSN: 1432-1203
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract X-linked liver glycogenosis (XLG) resulting from phosphorylase kinase (Phk) deficiency is one of the most common forms of glycogen storage disease. It is caused by mutations in the gene encoding the liver isoform of the Phk α subunit (PHKA2). In the present study, we address the issue of phenotypic and allelic heterogeneity in XLG. We have identified mutations in seven male patients. One of these patients represents the variant biochemical phenotype, XLG subtype 2 (XLG2), where Phk activity is low in liver but normal or even elevated in erythrocytes. He carries a K189E missense mutation, which adds to the emerging evidence that XLG2 is associated with missense mutations clustering at a few sites. Two patients display clinical phenotypes unusual for liver Phk deficiency, with dysfunction of the kidneys (proximal renal tubular acidosis) or of the nervous system (seizures, delayed cognitive and speech abilities, peripheral sensory neuropathy), respectively, in addition to liver glycogenosis. In the patient with kidney involvement, we have identified a missense mutation (P399S) and a trinucleotide deletion (2858del3) leading to the replacement of two amino acids by one new residue (N953/L954I), and a missense mutation has also been found in the patient with neurological symptoms (G1207W). These two cases demonstrate that PHKA2 mutations can also be associated with uncommon clinical phenotypes. Finally, in four typical XLG cases, we have identified three truncating mutations (70insT, R352X, 567del22) and an in-frame deletion of eight well-conserved amino acids (2452del24). Together, this study adds eight new mutations to the previously known complement of sixteen PHKA2 mutations. All known PHKA2 mutations but one are distinct, indicating pronounced allelic heterogeneity of X-linked liver glycogenosis with mutations in the PHKA2 gene.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004390050715
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  • 2
    Electronic Resource
    Electronic Resource
    Molecular basis of quantitative structure-properties relationships (QSPR): A quantum similarity approach (1999)
    Springer
    Journal of computer aided molecular design 13 (1999), S. 259-270 
    Details
    ISSN: 1573-4951
    Keywords: log P ; molecular quantum similarity measures ; quantitative structure-properties relationships (QSPR) ; substituent effect
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Since the dawn of quantitative structure-properties relationships (QSPR), empirical parameters related to structural, electronic and hydrophobic molecular properties have been used as molecular descriptors to determine such relationships. Among all these parameters, Hammett σ constants and the logarithm of the octanol- water partition coefficient, log P, have been massively employed in QSPR studies. In the present paper, a new molecular descriptor, based on quantum similarity measures (QSM), is proposed as a general substitute of these empirical parameters. This work continues previous analyses related to the use of QSM to QSPR, introducing molecular quantum self-similarity measures (MQS-SM) as a single working parameter in some cases. The use of MQS-SM as a molecular descriptor is first confirmed from the correlation with the aforementioned empirical parameters. The Hammett equation has been examined using MQS-SM for a series of substituted carboxylic acids. Then, for a series of aliphatic alcohols and acetic acid esters, log P values have been correlated with the self-similarity measure between density functions in water and octanol of a given molecule. And finally, some examples and applications of MQS-SM to determine QSAR are presented. In all studied cases MQS-SM appeared to be excellent molecular descriptors usable in general QSPR applications of chemical interest.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1008059505361
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  • 3
    Electronic Resource
    Electronic Resource
    Use of electron-electron repulsion energy as a molecular descriptor in QSAR and QSPR studies (2000)
    Springer
    Journal of computer aided molecular design 14 (2000), S. 477-485 
    Details
    ISSN: 1573-4951
    Keywords: electron-electron repulsion energy ; molecular descriptor ; molecular quantum similarity measures ; QSAR ; QSPR
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Electron-electron repulsion energy (〈 Vee〉) is presented as a new molecular descriptor to be employed in QSAR and QSPR studies. Here it is shown that this electronic energy parameter is connected to molecular quantum similarity measures (MQSM), and as a consequence can be considered as a complement to steric and electronic parameters in description of molecular properties and biological responses of organic compounds. The present strategy considers the molecule as a whole, thus there is no need to employ contributions of isolated fragments as in many calculations of molecular descriptors, like log P or the Free–Wilson analysis. The procedure has been tested in a widespread set of molecules: alcohols, alkanamides, indole derivatives and 1-alkylimidazoles. Molecular properties, as well as toxicity, are correlated using 〈 Vee〉 as a parameter, and extensions to the method are given for handling difficult systems. In almost all studied cases, satisfactory linear relationships were finally obtained.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1008136520396
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  • 4
    Electronic Resource
    Electronic Resource
    Quantum chemistry, Sobolev spaces and SCF (2000)
    Springer
    Journal of mathematical chemistry 28 (2000), S. 59-70 
    Details
    ISSN: 1572-8897
    Keywords: quantum chemistry ; Sobolev spaces ; Schrödinger equation ; extended wavefunctions ; kinetic energy ; Sobolev transformation ; SCF theory ; generalised secular equations ; LCAO-MO theory
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mathematics
    Notes: Abstract Extended wavefunctions, including the wavefunction gradient, and the norm induced Sobolev spaces are presented as a mathematical structure well adapted to the approximate quantum-chemical formalism, customarily used to handle the Schrödinger equation. A useful application, related to the solution of SCF Euler equations in matrix form, is also analysed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1018892326762
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  • 5
    Electronic Resource
    Electronic Resource
    Toward a global maximization of the molecular similarity function: Superposition of two molecules (1997)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Computational Chemistry 18 (1997), S. 826-846 
    Details
    ISSN: 0192-8651
    Keywords: molecular quantum similarity measures (MQSM) ; atomic shell approximation (ASA) ; global maximization ; molecular alignments ; Chemistry ; Theoretical, Physical and Computational Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Computer Science
    Notes: A quantum similarity measure between two molecules is normally identified with the maximum value of the overlap of the corresponding molecular electron densities. The electron density overlap is a function of the mutual positioning of the compared molecules, requiring the measurement of similarity, a solution of a multiple-maxima problem. Collapsing the molecular electron densities into the nuclei provides the essential information toward a global maximization of the overlap similarity function, the maximization of which, in this limit case, appears to be related to the so-called assignment problem. Three levels of approach are then proposed for a global search scanning of the similarity function. In addition, atom - atom similarity Lorentzian potential functions are defined for a rapid completion of the function scanning. Performance is tested among these three levels of simplification and the Monte Carlo and simplex methods. Results reveal the present algorithms as accurate, rapid, and unbiased techniques for density-based molecular alignments. © 1997 by John Wiley & Sons, Inc. J Comput Chem 18: 826-846, 1997
    Additional Material: 21 Ill.
    Type of Medium: Electronic Resource
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    Paper (German National Licenses)
  • 6
    Electronic Resource
    Electronic Resource
    Molecular quantum similarity measures as an alternative to log P values in QSAR studies (1998)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Computational Chemistry 19 (1998), S. 1575-1583 
    Details
    ISSN: 0192-8651
    Keywords: 1-octanol/water partition coefficient ; molecular quantum similarity measures ; atomic shell approximation ; promolecular densities ; QSAR ; Chemistry ; Theoretical, Physical and Computational Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Computer Science
    Notes: A new molecular descriptor of hydrophobicity based on molecular quantum similarity measures (MQSM), which can be used to replace the log P parameter in QSAR studies, is proposed. Unlike the majority of existing approaches for calculation of log P, the present methodology does not rely on the use of fragment additive contributions, but rather it is based on the comparison of quantum chemically calculated electron density distributions of a given molecule in water and in 1-octanol, using MQSM. The method has been tested on a broad series of 58 molecules including such structural types as aliphatic hydrocarbons, alcohols, amines, halides, carboxylic acids, esters, amides, and ketones, as well as more complex systems with two functional groups. In all cases investigated, an excellent linear relationship between calculated MQSM and log P values was found. Additionally, an example of QSAR analysis is presented using MQSM instead of log P values, corresponding to predict the narcosis of tadpoles.   © 1998 John Wiley & Sons, Inc.   J Comput Chem 19: 1575-1583, 1998
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Quantum similarity measures under atomic shell approximation: First order density fitting using elementary Jacobi rotations (1997)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Computational Chemistry 18 (1997), S. 2023-2039 
    Details
    ISSN: 0192-8651
    Keywords: atomic shell approximation ; Carbó Index ; elementary Jacobi rotations ; promolecular densities ; quadratic error integral function ; quantum similarity measures ; Chemistry ; Theoretical, Physical and Computational Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Computer Science
    Notes: The elementary Jacobi rotations technique is proposed as a useful tool to obtain fitted electronic density functions expressed as linear combinations of atomic spherical shells, with the additional constraint that all coefficients are kept positive. Moreover, a Newton algorithm has been implemented to optimize atomic shell exponents, minimizing the quadratic error integral function between ab initio and fitted electronic density functions. Although the procedure is completely general, as an application example both techniques have been used to compute a 1S-type Gaussian basis for atoms H through Kr, fitted from a 3-21G basis set. Subsequently, molecular electronic densities are modeled in a promolecular approximation, as a simple sum of parameterized atomic contributions. This simple molecular approximation has been employed to show, in practice, its usefulness to some computational examples in the field of molecular quantum similarity measures.   © 1997 John Wiley & Sons, Inc.   J Comput Chem 18: 2023-2039, 1997
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
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