Cleaning compositions for solid surfaces – auxiliary compositions – Cleaning compositions or processes of preparing – Enzyme component of specific activity or source
Patent
1993-10-22
1999-06-22
Fries, Kery
Cleaning compositions for solid surfaces, auxiliary compositions
Cleaning compositions or processes of preparing
Enzyme component of specific activity or source
510530, 435188, 435209, C11D 3386, C12N 920
Patent
active
059143061
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
This invention relates to novel stabilized enzymes. More specifically the invention relates to novel stabilized enzymes, in which a naturally occurring amino acid residue (other than proline) has been substituted with a proline residue at one or more positions; at which position(s) the dihedral angels .phi. (phi) constitute values within the interval and .psi. (psi) constitute values within the intervals -80<.psi.<10 or .lambda.100<.psi.<180!; and which position(s) is/are not located in regions in which the enzyme is characterized by possessing .alpha.-helical or .beta.-sheet structure.
The invention also relates to nucleotide sequences encoding the novel stabilized enzymes, and expression vectors and host organisms containing the nucleotide sequences. The invention also relates to detergent compositions comprising the stabilized enzymes.
BACKGROUND ART
The Structure of Proteins
Enzymes are globular proteins and quiet compact due to the considerable amount of folding of the long polypeptide chain. The polypeptide chain essentially consists of the "backbone" and its "side-groups". As the peptide bond is planar, only rotations around the C.sub..alpha. --N axis and the C.sub..alpha. --C.sup.' axis are permitted. Rotation around the C.sub..alpha. --N bond of the peptide backbone is denoted by the torsion angle .phi. (phi), rotation around the C.sub..alpha. --C' bond by .psi. Company, New York!. The choice of the values of these angles of rotation is made by assigning the maximum value of +180.degree. (which is identical to +180.degree.) to the maximally extended chain. In the fully extended polypeptide chain, the N.sub.1 C.sub..alpha. and C' atoms are all "trans" to each other. In the "cis" configuration, the angles .phi. and .psi. are assigned the value of 0.degree.. Rotation from this position around the bonds, so that the atoms viewed behind the rotated bond move "counterclockwise", are assigned negative values by definition, those "clockwise" are assigned positive values. Thus, the values of the torsion angles lie within the range -180.degree. to +180.degree..
Since the C.sub.60 -atoms are the swivel point for the chain, the side-groups (R-groups) associated with the C.sub.60 -atoms become extremely important with respect to the conformation of the molecule.
The term "conformation" defines the participation of the secondary and tertiary structures of the polypeptide chains in moulding the overall structure of a protein. The correct conformation of a protein is of prime importance to the specific structure of a protein and contributes greatly to the unique catalytic properties (i.e. activity and specificity) of enzymes and their stability.
The amino acids of polypeptides can be divided into four general groups: nonpolar, uncharged polar, and negatively or positively charged polar amino acids. A protein molecule, when submerged in its aqueous environment in which it normally occurs, tends to expose a maximum number of its polar side-groups to the surrounding environment, while a majority of its nonpolar sidegroups are oriented internally. Orientation of the side-groups in this manner leads to a stabilization of protein conformation.
Proteins, thus, exist in a dynamic equilibrium between a folded and ordered state, and an unfolded and disordered state. This equilibrium in part reflects the short range interactions among the different segments of the polypeptide chain, which tends to stabilize the overall structure of proteins. Thermodynamic forces simultaneously tend to promote randomization of the unfolding molecule.
A way to engineer stabilized proteins is to reduce the extend of unfolding by decreasing the flexibility of the polypeptide backbone, and simultaneously decreasing the entropy of the unfolded chain. So far only few attempts have been made to implement this rationale in the development of novel stabilized enzymes.
A genera principle of increasing protein thermostability has been provided states that the thermostability of a globular protein can be enhanced cumul
REFERENCES:
patent: 4738682 (1988-04-01), Boegh et al.
Chou et al, J. Mol. Biology .beta.-Turns in Proteins vol. 115, pp. 135-175, 1977.
T.E. Greighton, J. Mol. Biol. Implications of Many Proline Residues for Kinetics of Protein Folding and Unfolding, vol. 125, pp. 401-406, 1978.
M. Levitt, Preferences of Amino Acids, vol. 17, No. 20, 1978.
Anant Patkar Shamkant
Borch Kim
Clausen Ib Groth
Osten Claus von der
Svendsen Allan
Fries Kery
Lambiris Elias J.
Novo Nordisk A S
Zelson Steve T.
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