This template was developed by Overleaf and the National Academy of Science to allow authors to prepare and edit their Contributed or Direct Submission manuscripts. Authors can then submit manuscripts to PNAS by using the PDF and source files generated by ShareLaTeX, Overleaf or another compiler. The template will work for both regular and Plus research reports.
Additional instructions for direct submission and editing on Overleaf are included. The original template is available here: https://www.overleaf.com/latex/templates/template-for-preparing-your-research-report-submission-to-pnas-using-overleaf/fzcbzjvpvnxn#.WmsjQZM-fVp