Site-directed modification of factor IX

A factor, average molecular weight technology, applied in the field of modified factor IX polypeptides, which can solve problems such as defect coagulation

Inactive Publication Date: 2011-05-18
BAYER HEALTHCARE LLC
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Insufficient levels of FIX lead to defective coagulation and symptoms from uncontrolled bleeding

Method used

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  • Site-directed modification of factor IX
  • Site-directed modification of factor IX
  • Site-directed modification of factor IX

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0114] Embodiment 1: computer analysis (in silico analysis)

[0115] In silico analysis was performed to evaluate FIX residues at sites that are likely to be successfully used for cysteine ​​substitution for site-specific polymer conjugation. The analysis focused on lysine, phenylalanine, and leucine residues because these charged residues are more commonly solvent exposed and because in the case of FVIII these Cystine has been the most successfully used site for polymer conjugation (see eg, US Publication No. 2006 / 0115876). Solvent exposure of lysine, phenylalanine, and leucine residues within FIX was determined using data from the crystal structure of FIX (Hopfner et al., Structure 7:989-996, 1999). Other potentially solvent exposed residues were also considered as possible sites for cysteine ​​substitution. The computer algorithm FoldX was used to predict the effect of mutation of each residue to cysteine ​​on the free energy of both the individual residues and the overal...

Embodiment 2

[0123] Example 2: Activating peptides

[0124] To identify potential modification sites in activating peptides that would not disrupt post-translational modifications, the amino acid sequences of activating peptides from 8 species were aligned to identify evolutionarily conserved regions ( Figure 4 ). Amino acids that are not conserved across species are unlikely to be required for FIX function (including post-translational modifications) and were therefore selected for mutation to cysteine. In addition, residues that were part of the consensus sequence of the two N-linked glycosylation sites and the site of Tyr155 tyrosine sulfation and O-linked glycosylation and phosphorylation were avoided. Based on this analysis, four amino acid residues (V153, T163, L165, F175) were selected for mutation to cysteine.

[0125]As another method of site-specific modification of FIX, 4 of the 7 glycosylation sites (T148, N167, T169, T172) in the activation peptide were converted to cystein...

Embodiment 3

[0127] Example 3: Expression and Activity

[0128] Based on the computer analysis described above, a total of 14 residues were selected as potential sites for modification, and all 14 residues were changed to cysteine ​​by site-directed mutagenesis of the plasmid pAGE16-FIX, which -FIX contains the human FIX coding region cloned in the expression vector pAGE16 ( image 3 ). Another FIX mutein was created in which a single cysteine ​​residue was inserted between A161 and E162 to create a 162C mutein. A consensus Kozak sequence has been added just 5' to the ATG start codon in all plasmids to ensure efficient translation initiation. The sequence of the altered FIX coding sequence was confirmed by double-stranded DNA sequencing of the entire coding region. The wild-type pAGE16-FIX plasmid and various mutant plasmids were transiently transfected into HKB11 cells, a human cell line generated by fusion of HEK293 cells with B-cell lymphoma. When various cell lines (CHO, BHK21, HKB...

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Abstract

The invention relates to modified Factor IX polypeptides such as Factor IX polypeptides with one or more introduced cysteine sites. The modified Factor IX polypeptides may be conjugated to a biocompatible polymer. The invention also relates to methods of making modified Factor IX polypeptides, and methods of using modified Factor IX polypeptides, for example, to treat patients afflicted with hemophilia B.

Description

[0001] This application claims the benefit of US Provisional Application Serial No. 61 / 124,568, filed April 16, 2008, the contents of which are hereby incorporated by reference in their entirety. field of invention [0002] The present invention relates to modified Factor IX polypeptides, such as Factor IX polypeptides having one or more introduced cysteine ​​sites. Modified Factor IX polypeptides can be coupled to biocompatible polymers. The invention also relates to methods of producing modified Factor IX polypeptides, and methods of using modified Factor IX polypeptides, for example, to treat patients afflicted with hemophilia B. Background of the invention [0003] Hemophilia B affects 1 in 34,500 men and is caused by multiple genetic defects in the gene encoding clotting factor IX (FIX), which result in low or undetectable levels of the FIX protein in the blood (Kurachi et al., Hematol. Oncol. Clin. North Am. 6:991-997, 1992; Lillicrap, Haemophilia 4:350-357, 1998). I...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): A61K38/48
CPCA61K47/48215C12Y304/21022C12N9/644A61K38/00A61K47/60A61P7/04
Inventor 艾伦·R·布鲁克斯约翰·E·墨菲马里安·塞托蒋晓乔戴维·基夫利科钱德拉·帕特尔
Owner BAYER HEALTHCARE LLC
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