Vector and axial-vector structures of the Theta^+

We present in this talk recent results of the vector and axial-vector transitions of the nucleon to the pentaquark baryon Theta^{+}, based on the SU(3) chiral quark-soliton model. The results are summarized as follows: K^{}-N-Theta vector and tensor coupling constants turn out to be g_{K^{}N Theta} = 0.81 and f_{K^{}N Theta}=0.84, respectively, and the KN Theta axial-vector coupling constant to be g_{A}^ = 0.05. As a result, the total decay width for Theta^+ to NK becomes very small: Gamma_{Theta -> NK} = 0.71 MeV, which is consistent with the DIANA result Gamma_{Theta -> NK}=0.36 ± 0.11 MeV.