No, the ERS in Texas is not an IRA, but is a defined benefit plan (like a pension or annuity). See https://www.ers.texas.gov/Active-Employees/Retirement/State-of-Texas-Retirement
Can you deduct these contributions? Probably not. You appear to have several choices on which plan you have: 401(k), 457, traditional, Roth - and I don't know which one you have. But note that Roth account contributions are not deductible and that the non-Roth account contributions were probably already taken out of your income on your W-2, so can't be deducted again.
However, contributions to any of these plans are probably eligible for the Retirement Savings Tax Credit (which TurboTax will handle automatically, if you are eligible).
You might have a talk with your benefits co-ordinator about which plan you have.
