Example: PKI NES LALKLAGLDI

2-2-1: {F/I/L/M/V}{XX}{F/I/L/M/V}{XX}{F/I/L}{X; not:F/I/L/M/V/W}{F/I/L/M/V}

Example: HIV-1 Rev NES LPPLERLTL

2-3-1: {F/I/L/M/V}{XX}{F/I/L/M/V}{XXX}{F/I/L}{X; not:F/I/L/M/V/W}{F/I/L/M/V}

Example: p53 NES FRELNEALEL