June 2 (Reuters) - Four blank-check companies, backed by venture investor Chamath Palihapitiya, are looking to raise a total of $800 million through initial public offerings with a focus on acquiring biotechnology firms, regulatory filings showed on Wednesday. The new companies, Social Capital Suvretta Holdings Corp I, II, III and VI, said they planned to list on the Nasdaq and will not offer warrants. Reporting by Eva Mathews in Bengaluru; Editing by Shinjini Ganguli Our Standards: The Thomson Reuters Trust Principles.