ðɪs dˈɪfɹəns ɹɪzˈʌlts fɹʌmðə fˈækt ðæt sˈʌbjuːnˌɪt ɐdˈɪʃən æt ðə mˈaɪnəs ˈɛnd ɹᵻkwˈaɪɚz ɐ kɑːnfoːɹmˈeɪʃənəl tʃˈeɪndʒ ʌvðə sˈʌbjuːnˌɪts.
This difference results from the fact that subunit addition at the minus end requires a conformational change of the subunits.