Horace, Satires, vol. 2, 1, line 60 ff.
metuo: I fear; this is the main clause. There are two dependent clauses.. . .' 'o puer, ut sis
vitalis metuo et maiorum nequis amicus
frigore te feriat.' '. . .
ut sis vitalis: that you may not live long. This is one of the dependent clauses.
maiorum nequis amicus frigore te feriat: that a powerful friend may grow cold toward you. This is the other dependent clause.
Here is the grammar rationale in Allen and Greenough:
564. Verbs of fearing take the Subjunctive, with nē affirmative and nē nōn or ut negative.
In this use nē is commonly to be translated by that, ut and nē nōn by that not:—
“timeō nē Verrēs fēcerit ” (Verr. 5.3) , I fear that Verres has done, etc.
“ nē animum offenderet verēbātur ” (B. G. 1.19) , he feared that he should hurt the feelings, etc.
“ nē exhērēdārētur veritus est ” (Rosc. Am. 58) , he feared that he should be disinherited.
“ōrātor metuō nē languēscat senectūte ” (Cat. M. 28) , I fear the orator grows feeble from old age.
“vereor ut tibi possim concēdere ” (De Or. 1.35) , I fear that I cannot grant you.
“haud sānē perīculum est nē nōn mortem optandam putet ” (Tusc. 5.118) , there is no danger that he will not think death desirable.