The possibility of excess electron binding to cystine (consisting of two L-cysteine molecules linked via a disulfide bridge) in the gas-phase was studied at the second-order Moller-Plesset perturbation theory (MP2) level using the 6-31+G**+6(sp) basis sets. Several geometrically stable conformers and tautomers were found on the potential energy surfaces (PES) of both the neutral and anionic species. The most stable neutral isomer has proven to (i) involve two canonical rather than zwitterionic cysteine monomers, (ii) possess no inter-monomer hydrogen bonds, and (iii) exhibit an extended structure due to the presence of four intramonomer hydrogen bonds. It has also been found that most neutral isomers are capable of excess electron binding to form geometrically and electronically stable anions of dipole-bound nature. The electron binding energies for these anions span a wide region of 0.0004-0.947 eV (depending on the neutral parent molecule). In addition, several cystine-based anions were found at geometries where the neutral species are not stable. The latter anions gain stability from their large electron binding energies (they bind an excess electron by 0.488-1.975 eV).