Appeal No. 1999-1774
Application No. 08/487,183
emitted light. One of ordinary skill in the art would reasonably
expect that the introduction of other amino acids into these
positions would produce mutant enzymes with additional colors of
emitted light as each amino acid has different chemical properties
(i.e., charge, polarity, hydrophobicity etc.) and therefore would alter
the environment around the luciferin substrate in different ways.
Id., page 7.
The examiner also concluded that it would have been “obvious to mutate
other amino acids within the region of amino acids 223-247.” Id. She found
motivation to do so based on the following passage in the Wood dissertation:
The three substitutions that cause most of the color shift between
yellow green and orange are located in a 25-amino acid segment of
the sequences, from positions 223-247. The probability of this
occurring by chance is about 0.01. . . . [I]t is likely that this region
contains many, if not most, of the potentially suitable amino acids
that affect the color of luminescence. It is expected that such a
region would be close to the binding site of luciferin.
Wood dissertation, page 221.
Appellants argue that the cited references would not have rendered the
claimed luciferase mutants obvious to those of ordinary skill in the art.
Appellants argue that the cited references would not have made it obvious to
alter amino acid positions other than the three positions taught by the references
to be important to light color, nor would they have made it obvious to make
substitutions other than the naturally occurring variations at those three positions.
“In rejecting claims under 35 U.S.C. § 103, the examiner bears the initial
burden of presenting a prima facie case of obviousness.” In re Rijckaert, 9 F.3d
1531, 1532, 28 USPQ2d 1955, 1956 (Fed. Cir. 1993). “‘Obviousness cannot be
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