Abstract: The present invention is directed to modified CFTR proteins or fragments thereof that contain single or multiple amino acid mutations to improve the structural stability of such CFTR proteins and/or fragments. Specifically, the modified CFTR proteins or fragment thereof differ from the wild-type human CFTR protein or fragment thereof by the presence of four or more mutations selected from V150D, M470V, S492P, F494N, S495P, A534P, I539T, G550E, G551D, R553Q, R555K, Q637R, S1255L, K1334G, S1359A, E1371Q, H1402S, Q1411D, and any combination thereof, such that the stability of the polypeptide is increased relative to that of the wild-type human CFTR polypeptide or fragment thereof.

Abstract: The present invention is directed to modified CFTR proteins or fragments thereof that contain single or multiple amino acid mutations to improve the structural stability of such CFTR proteins and/or fragments. Specifically, the modified CFTR proteins or fragment thereof differ from the wild-type human CFTR protein or fragment thereof by the presence of four or more mutations selected from V150D, M470V, S492P, F494N, 5495P, A534P, I539T, G550E, G551D, R553Q, R555K, Q637R, 51255L, K1334G, 51359A, E1371Q, H14025, Q1411D, and any combination thereof, such that the stability of the polypeptide is increased relative to that of the wild-type human CFTR polypeptide or fragment thereof.

Abstract: The present invention provides codon optimization to increase protein production by providing a target gene, wherein the expression of the target gene is to be optimized; determining one or more low-frequency codons in the target gene; providing a codon usage frequency table; replacing each of the one or more low-frequency codons in the target gene with a corresponding high-frequency codons that code for the same amino acid; and harmonizing the a distribution of codon frequencies to those of the set of highly expressed native gene over an open reading frame in the target gene to form an optimized gene, wherein the optimized gene encodes an amino acid sequence identical to the respective wild-type (native) amino acid sequence.