Catalyzes the ATP-dependent condensation of GlcN-Ins and L-cysteine to form L-Cys-GlcN-Ins. 1D-myo-inositol 2-amino-2-deoxy-alpha-D-glucopyranoside + ATP + L-cysteine = 1D-myo-inositol 2-(L-cysteinylamino)-2-deoxy-alpha-D-glucopyranoside + AMP + diphosphate + H(+) Binds 1 zinc ion per subunit. Monomer. Belongs to the class-I aminoacyl-tRNA synthetase family. MshC subfamily.