Patent ID: 7598365

Claim:
An isolated DNA fragment comprising a nucleotide sequence encoding the amino acid sequence of SEQ ID NO:1, wherein the nucleotide sequence has a GC content of about 50% to about 60%, provided that i) said nucleotide sequence does not comprise a nucleotide sequence of GATAAT, TATAAA, AATATA, AATATT, GATAAA, AATGAA, AATAAG, AATAAA, AATAAT, AACCAA, ATATAA, AATCAA, ATACTA, ATAAAA, ATGAAA, AAGCAT, ATTAAT, ATACAT, AAAATA, ATTAAA, AATTAA, AATACA or CATAAA; ii) said nucleotide does not comprise a nucleotide sequence of CCAAT, ATTGG, GCAAT or ATTGC; iii) said nucleotide sequence does not comprise a sequence of ATTTA, AAGGT, AGGTA, GGTA or GCAGG; iv) said nucleotide sequence does not comprise a GC stretch consisting of 7 consecutive nucleotides of G or C; v) said nucleotide sequence does not comprise a AT stretch consisting of 5 consecutive nucleotides of A or T; and vi) said nucleotide sequence does not comprise the codons TTA, CTA, ATA, GTA, TCG, CCG, ACG or GCG.