In　this　work,　the　mechanism　of　domain　movements　of　glutamine-binding　protein　(GlnBP),　especially　the　influence　of　the　ligand　on　GlnBP　dynamic　behavior　is　investigated　with　the　aid　of　a　Gaussian　network　model　(GNM)　and　an　anisotropy　elastic　network　model.　The　results　show　that　the　＂open-closed＂　transition　mainly　appears　as　the　large　movement　of　the　small　domain,　especially　the　top　region　including　two　alpha-helices　and　two　beta-strands.　The　slowest　mode　of　each　three　forms　of　GlnBP-ligand-free　open,　ligand-bound　closed,　and　ligand-free　closed　GlnBP-shows　that　the　open-closed　motion　of　the　two　domains　has　a　common　hinge　axis　centered　on　Lys-87　and　Gln-183.　Accompanying　the　conformational　transition,　the　residues　within　both　large　and　small　domains　move　in　a　highly　coupled　way.　The　peaks　of　the　fast　modes　correspond　to　residues　that　were　thought,　in　the　GNM,　to　be　important　for　the　stability　of　the　protein,　and　these　residues　may　be　involved　in　the　interactions　with　the　membrane-bound　components.　With　the　contacts　between　the　large　domain　and　the　small　domain　increasing,　the　ability　of　the　＂open-closed＂　motion　is　decreased.　All　the　results　agree　well　with　those　of　molecular　dynamics　simulations,　and　it　is　thought　that　the　open-closed　conformation　transition　is　the　nature　of　the　topology　structure　of　GlnBP.　Also,　the　influence　of　the　ligand　on　GlnBP　is　studied　with　a　modified　GNM　method.　The　results　obtained　show　that　the　ligand　does　not　influence　the　closed-to-open　transition　tendency.