Front Matter

5.3 Modeling and engineering of fatty acid specificity 89

Figure 1. Comparison of the shape of binding pockets ofRhizomucor mieheilipase (RML) andCan-
dida antarcticalipase B (CALB) (Pleiss et al., 1998). Three perpendicular cross-sections through the
proteins are shown. A model of the fatty acid is displayed; a number indicates the length of the longest
fatty acid which completely binds inside the binding pocket.

Table 1.Mutations in the scissile fatty acid binding site of lipases fromRhizopus delemarandRhizopus
oryzae, and their effect on chain length specificity (Pleiss et al., 1998). Equivalent residues in the ho-
mologous RML (see Figure 2) are given in parentheses.

Source Mutation Structural effect
of the mutation

Experimental observation

R. oryzae F95Y (F94) Blocks binding at C 12 60 % (30 %) increase of caproic
acid methyl ester relative to oleic
(stearic) acid

R. delemar F95D (F94) Hydrophilic at C 12 2- fold decrease of hydrolysis

R. delemar F95D (F94)
F214R (F213)

Right wall of hydrophobic

crevice becomes hydrophilic

(C 10 –C 16 )

3-fold increase of tricaprylin

relative to triolein

R. delemar F112W (F111) Blocks binding at C 6 50 % increase of tributyrin
relative to triolein

R. delemar F112Q (F111) Hydrophilic at C 6 no activity

R. delemar V206T (V205) Hydrophilic at C 4 10–20 % activity

R. delemar V209W
(L208)

Blocks binding at C 10 2-fold increase of tributyrin

relative to triolein

R. delemar V209W (L208)
F112W (F111)

Blocks binding at C 10 and C 6 80-fold increase of tributyrin

relative to tricaprylin; no

triolein hydrolysis

R. oryzae F214Y (F213) Blocks binding at C 16 20 % increase of caproic acid
methyl ester relative to oleic
and stearic acid