Riboswitches　are　noncoding　mRNA　segments　that　can　regulate　the　gene　expression　via　altering　their　structures　in　response　to　specific　metabolite　binding.　We　proposed　a　coarse-grained　Gaussian　network　model　(GNM)　to　examine　the　unfolding　and　folding　dynamics　of　adenosine　deaminase　(add)　A-riboswitch　upon　the　adenine　dissociation,　in　which　the　RNA　is　modeled　by　a　nucleotide　chain　with　interaction　networks　formed　by　connecting　adjoining　atomic　contacts.　It　was　shown　that　the　adenine　binding　is　critical　to　the　folding　of　the　add　A-riboswitch　while　the　removal　of　the　ligand　can　result　in　drastic　increase　of　the　thermodynamic　fluctuations　especially　in　the　junction　regions　between　helix　domains.　Under　the　assumption　that　the　native　contacts　with　the　highest　thermodynamic　fluctuations　break　first,　the　iterative　GNM　simulations　showed　that　the　unfolding　process　of　the　adenine-free　add　A-riboswitch　starts　with　the　denature　of　the　terminal　helix　stem,　followed　by　the　loops　and　junctions　involving　ligand　binding　pocket,　and　then　the　central　helix　domains.　Despite　the　simplified　coarse-grained　modeling,　the　unfolding　dynamics　and　pathways　are　shown　in　close　agreement　with　the　results　from　atomic-level　MD　simulations　and　the　NMR　and　single-molecule　force　spectroscopy　experiments.　Overall,　the　study　demonstrates　a　new　avenue　to　investigate　the　binding　and　folding　dynamics　of　add　A-riboswitch　molecule　which　can　be　readily　extended　for　other　RNA　molecules.　Published　by　AIP　Publishing.