  Recently Lunin and Maldacena used an SL(3,R) transformation of the AdS_5 x
S^5 background to generate a supergravity solution dual to a so-called
beta-deformation of N = 4 super Yang-Mills theory. We use a
T-duality-shift-T-duality (TsT) transformation to obtain the beta-deformed
background for real beta, and show that solutions of string theory equations of
motion in this background are in one-to-one correspondence with those in AdS_5
x S^5 with twisted boundary conditions imposed on the U(1) isometry fields. We
then apply the TsT transformation to derive a local and periodic Lax pair for
the bosonic part of string theory in the beta-deformed background. We also
perform a chain of three consecutive TsT transformations to generate a
three-parameter deformation of AdS_5 x S^5. The three-parameter background is
dual to a nonsupersymmetric marginal deformation of N=4 SYM. Finally, we
combine the TsT transformations with SL(2,R) ones to obtain a 6+2 parameter
deformation of AdS_5 x S^5.
