if compiling with xelatex, and the fonts 'Linux Libertine' and 'Asana Math' are available, will typeset more like what PNAS is doing. quotes are messed up, though
\documentclass[11pt,leqno]{amsart}
%\usepackage{amsthm}
\newcommand{\pathtotrunk}{../../}
\input{\pathtotrunk text/article_preamble}
\input{\pathtotrunk text/top_matter}
\input{\pathtotrunk text/kw_macros}
\begin{document}
\input{A-infty}
\input{gluing}
\end{document}