Enable and Shutdown pins are basically the same thing just named with a different a emphasis. Also consider that such pins can also be either active low or active high. So...
Active LO Enable = Active HI Shutdown
Active HI Enable = Active LO Shutdown
So basically you need the equivalent of a NOT gate with an appropriate output (push-pull or open-collector/drain) depending on what you are driving. This can be accomplished with an actual logic gate or a pull-down transistor + pull-up resistor or a totem pole or whatever.
If you take a look at your circuit there, Q1 and R2 already invert the base of Q1. So if you need to invert it again it you just run your SHTDWN output through another set of those.