B757 Captain reported loss of TAT probe at cruise causing loss of autoflight and other systems. Captain unable to restore systems and diverted for a normal landing.

Narrative

In cruise; night time; passing south of Location A; the autopilot and auto-throttle disengaged. The First Officer continued flying. We tried reengaging the autopilot and auto-throttle; but could not.The EICAS messages; AUTOTHROT DISC; R ENG EEC; L ENG EEC; TAT PROBE;" were displayed. A line through LNAV and VNAV appeared on the FMA. The First Officer took the radio and flew. I did the QRH appropriate checklists. No resets were available. ATC was informed of the loss of autoflight. We were unable to maintain RVSM airspace due to no autopilot and started a descent. I spoke with Dispatch and briefly with Maintenance Control. Told them of the malfunction and inability to continue to destination.The reasoning behind decision to divert were several factors. It was still more than 3.5 hours to ZZZ1; no operational autopilot; autothrottle; LNAV or VNAV; it was dark; and we were going to cross over high terrain on our route and we were unable to maintain RVSM altitudes. We decided to divert to ZZZ; which we had just passed. The reasoning behind choosing ZZZ [was] it was VMC; had good approaches and runways; it is an Air Carrier X Hub with many options for the passengers and also an Air Carrier Maintenance station. We [requested priority] and asked for vectors to the approach.I spoke with the Purser and went through the briefing. Aircraft system malfunction; no imminent threat; but cannot continue to ZZZ1. Do not prepare for evacuation; we expect a normal landing. [No] specific instructions. Around 20 to 25 minutes [until landing]. I made an announcement to the passengers. I advised them that we were diverting to ZZZ due to a mechanical malfunction and that we expected a normal landing.I took the aircraft controls and the radios; while the First Officer briefed the approach. First Officer then took the aircraft controls once again while I did the Descent Checklist and sequentially the Landing Checklist. We got vectors for the ILS [Runway] X. I verified that the Flight Attendants were seated; and that the cabin was ready for landing. We flew a normal approach. The landing was smooth. We landed overweight at 211.1; max landing weight is 198. Emergency vehicles were present when we landed and they followed us to [the] Gate. After the arrival at the gate; we spoke with Maintenance and entered write ups in the ELB (Electronic Logbook). I spoke with Operations and the Chief Pilot.During this event; I felt that the First Officer and I used the resources available to us. CRM/TEM (Threat and Error Management) skills were used. The First Officer had very helpful inputs and kept up situational awareness; and advocated to ATC while I was heads down. It took a few minutes to locate the L (R) ENG EEC Non-normal Checklist; I first went to the EEC OFF-L(R) Checklist in the book as well.The passengers were very understanding and grateful for their safety. It would have been good if I had explained to them is that there would be emergency vehicles standing by; it worried them when they were seen. Perhaps I should have discussed the overweight landing with Dispatch before landing. It was a very busy event; the loss of automation increases the workload."