JOHANNESBURG (Reuters) - Lawyers for Jacob Zuma have until midnight to file papers outlining why nearly 800 corruption charges shelved before he became South African president eight years ago but recently reinstated by the courts should not be brought against him. The revival of the charges could increase pressure on Zuma to step down before his term ends in 2019 and diminish his influence over who succeeds him when the ruling African National Congress (ANC) chooses a new leader in December.     The 75-year-old president has faced and denied numerous other corruption allegations since taking office in 2009.  The 783 charges, which relate to a 30 billion rand ($2.2 billion) government arms deal arranged in the late 1990s, were filed but then dropped by the National Prosecuting Authority (NPA) shortly before he ran for the presidency. South Africa s High Court reinstated the charges last year and the Supreme Court upheld that decision in October, rejecting an appeal by Zuma and describing the NPA s decision to set aside the charges as  irrational . The NPA said then that Zuma had until Nov. 30 to make submissions before it decided whether to pursue the charges. Spokesmen for the NPA and Zuma were not available for comment on Thursday. Last month s Supreme Court ruling lifted the rand currency against the dollar as investors bet that Zuma s removal may be inching closer. The president is unpopular with many investors after sacking respected finance minister Pravin Gordhan in March, a move that hit South African financial assets and helped tip the country s credit ratings into  junk  territory. Infighting within the ruling ANC ahead of next month s conference to elect a successor to Zuma as party chief has also sapped confidence among the investors upon whom South Africa relies to finance its hefty budget and current account deficits. One of South Africa s leading universities, the University of the Witwatersrand (Wits) in Johannesburg, said on Thursday that it had appointed Gordhan as a visiting professor.  He will join other ANC heavyweights who have ended up at the Wits after being sidelined by Zuma, among them another respected and ousted finance minister, Nhlanhla Nene, and former Reserve Bank Governor Tito Mboweni. Widely seen as a competent and honest technocrat, Gordhan has become an unlikely poster boy for public anger at the president, whose administration has been marred by missteps and allegations of corruption. Zuma denies any wrongdoing. ($1 = 13.6794 rand) 
Deadline looms for South Africa's Zuma over revived graft charges