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Biomedical subjects

M I Kanehisa

Publications and source records attributed to M I Kanehisa.

10 recordsLinked to original sources

Los Alamos sequence analysis package for nucleic acids and proteins.

An interactive system for computer analysis of nucleic acid and protein sequences has been developed for the Los Alamos DNA Sequence Database. It provides a convenient way to search or verify various sequence features, e.g., restriction enzyme sites, protein coding frames, and properties of coded proteins. Further, the comprehensive analysis package on a large-scale database can be used for comparative studies on sequence and structural homologies in order to find unnoted information stored in nucleic acid sequences.

Amino Acid Sequence↗

Pattern recognition in nucleic acid sequences. I. A general method for finding local homologies and symmetries.

We present an algorithm--a generalization of the Needleman-Wunsch-Sellers algorithm--which finds within longer sequences all subsequences that resemble one another locally. The probability that so close a resemblance would occur by chance alone is calculated and used to classify these local homologies according to statistical significance. Repeats and inverted repeats may also be found. Results for both random and biological nucleic acid sequences are presented. Fourteen complete genomes are analyzed for dyad symmetries.

Amino Acid Sequence↗

Pattern recognition in nucleic acid sequences. II. An efficient method for finding locally stable secondary structures.

We present a method for calculating all possible single hairpin loop secondary structures in a nucleic acid sequence by the order of N2 operations where N is the total number of bases. Each structure may contain any number of bulges and internal loops. Most natural sequences are found to be indistinguishable from random sequences in the potential of forming secondary structures, which is defined by the frequency of possible secondary structures calculated by the method. There is a strong correlation between the higher G+C content and the higher structure forming potential. Interestingly, the removal of intervening sequences in mRNAs is almost always accompanied by an increase in the G+C content, which may suggest an involvement of structural stabilization in the mRNA maturation.

Base Composition↗

Structural changes and fluctuations of proteins. II. Analysis of the denaturation of globular proteins.

The statistical thermodynamic model of protein structure proposed in paper I is developed with special attention to the hydrophobic interaction. Calorimetric measurements of the thermal denaturation of five globular proteins, ribonuclease A, lysozyme, alpha-chymotrypsin, cytochrome c, and myoglobin, are quantitatively analyzed using the model. The thermodynamic parameters obtained by the least squares method reflect the global, average properties of proteins and are in good agreement with the expected values estimated from experimental and theoretical studies for model peptides. The average bond energy epsilon is well related to the tertiary structure of each protein. However, the difference in the parameters between different proteins is not observed for the cooperative energy ZJ and the chain entropy alpha. The individuality of a protein as far as its structural stability is concerned, is mainly reflected by the parameter gamma specifying the hydrophobic nature of a protein. The model is further applied in the analysis of several aspects of the structural stability of globular proteins. Denaturation induced by denaturants, salts, and pH are also explained by the model in a unified manner.

Calorimetry, Differential Scanning↗