The invention also relates to {TAIL ~ DNA constructs} encoding the variants, and to vectors and cells harboring {HEAD ~ the DNA constructs} 
The invention also relates to { TAIL ~ DNA constructs } encoding the variants , and to vectors and cells harboring { HEAD ~ the DNA constructs }
OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD