IntAct European Bioinformatics Institute IntAct intact http://www.ebi.ac.uk/ http://www.ebi.ac.uk/intact/query/${ac} EBI-[0-9]+|IA:[0-9]+ INTerAction database (IntAct) provides an open source database and toolkit for the storage, presentation and analysis of molecular interactions. http://www.ebi.ac.uk/intact European Bioinformatics Institute; Wellcome Trust Genome Campus; Hinxton, Cambridge; CB10 1SD; United Kingdom http://www.ebi.ac.uk/intact/ Ligand-induced asymmetry in histidine sensor kinase complex regulates quorum sensing. Ligand-induced asymmetry in histidine sensor kinase complex regulates quorum sensing. Cell (0092-8674) 2006 imex curation Neiditch MB., Federle MJ., Pompeani AJ., Kelly RC., Swem DL., Jeffrey PD., Bassler BL., Hughson FM. The 2.3A� resolution structure was determined using phases obtained by molecular replacement. hughson@princeton.edu 24-JAN-2007: Contacted by JYOTI. Only protein-protein interactions 3 in vitro In vitro x-ray diffraction x-ray crystallography X-ray X-ray x-ray diffraction predetermined predetermined participant predetermined Neiditch MB., Federle MJ., Pompeani AJ., Kelly RC., Swem DL., Jeffrey PD., Bassler BL., Hughson FM. The 2.3A� resolution structure was determined using phases obtained by molecular replacement. hughson@princeton.edu Accepted 2006-OCT-13 by DAVET. Cell (0092-8674) 2006 Only protein-protein interactions 3 imex curation Ligand-induced asymmetry in histidine sensor kinase complex regulates quorum sensing. Ligand-induced asymmetry in histidine sensor kinase complex regulates quorum sensing. Cell (0092-8674) 2006 imex curation Neiditch MB., Federle MJ., Pompeani AJ., Kelly RC., Swem DL., Jeffrey PD., Bassler BL., Hughson FM. The 2.3A� resolution structure was determined using phases obtained by molecular replacement. hughson@princeton.edu 24-JAN-2007: Contacted by JYOTI. Only protein-protein interactions 3 in vitro In vitro light scattering light scattering predetermined predetermined participant predetermined Neiditch MB., Federle MJ., Pompeani AJ., Kelly RC., Swem DL., Jeffrey PD., Bassler BL., Hughson FM. hughson@princeton.edu Accepted 2006-OCT-13 by DAVET. 24-JAN-2007: Contacted by JYOTI. Cell (0092-8674) 2006 Only protein-protein interactions 3 imex curation luxq_vibha Autoinducer 2 sensor kinase/phosphatase LuxQ luxQ protein protein vibha Vibrio harveyi MTTTRSNIKKRRSLATLITKIIILVLAPIILGIFIQSYYFSKQIIWQEVDRTKQQTSALIHNIFDSHFAAIQIHHDSNSKSEVIRDFYTDRDTDVLNFFFLSIDQSDPSHTPEFRFLTDHKGIIWDDGNAHFYGVNDLILDSLANRVSFSNNWYYINVMTSIGSRHMLVRRVPILDPSTGEVLGFSFNAVVLDNNFALMEKLKSESNVDNVVLVANSVPLANSLIGDEPYNVADVLQRKSSDKRLDKLLVIETPIVVNAVTTELCLLTVQDNQSVVTLQIQHILAMLASIIGMIMIALMSREWIESKVSAQLESLMSYTRSAREEKGFERFGGSDIEEFDHIGSTLESTFEELEAQKKSFRDLFNFALSPIMVWSEESVLIQMNPAARKELVIEDDHEIMHPVFQGFKEKLTPHLKMAAQGATLTGVNVPIGNKIYRWNLSPIRVDGDISGIIVQGQDITTLIEAEKQSNIARREAEKSAQARADFLAKMSHEIRTPINGILGVAQLLKDSVDTQEQKNQIDVLCHSGEHLLAVLNDILDFSKIEQGKFNIQKHPFSFTDTMRTLENIYRPICTNKGVELVIENELDPNVEIFTDQVRLNQILFNLVSNAVKFTPIGSIRLHAELEQFYGAENSVLVVELTDTGIGIESDKLDQMFEPFVQEESTTTREYGGSGLGLTIVKNLVDMLEGDVQVRSSKGGGTTFVITLPVKDRERVLRPLEVSQRIKPEALFDESLKVLLVEDNHTNAFILQAFCKKYKMQVDWAKDGLDAMELLSDTTYDLILMDNQLPHLGGIETTHEIRQNLRLGTPIYACTADTAKETSDAFMAAGANYVMLKPIKENALHEAFVDFKQRFLVERT AB2171F454C81060 luxp_vibha Autoinducer 2-binding periplasmic protein LuxP luxP protein protein vibha Vibrio harveyi MKKALLFSLISMVGFSPASQATQVLNGYWGYQEFLDEFPEQRNLTNALSEAVRAQPVPLSKPTQRPIKISVVYPGQQVSDYWVRNIASFEKRLYKLNINYQLNQVFTRPNADIKQQSLSLMEALKSKSDYLIFTLDTTRHRKFVEHVLDSTNTKLILQNITTPVREWDKHQPFLYVGFDHAEGSRELATEFGKFFPKHTYYSVLYFSEGYISDVRGDTFIHQVNRDNNFELQSAYYTKATKQSGYDAAKASLAKHPDVDFIYACSTDVALGAVDALAELGREDIMINGWGGGSAELDAIQKGDLDITVMRMNDDTGIAMAEAIKWDLEDKPVPTVYSGDFEIVTKADSPERIEALKKRAFRYSDN EB2A19FB91E21E54 luxp-luxq 1 4 unspecified role unspecified role neutral component neutral component c-terminal sufficient to bind sufficient binding region sufficient to bind certain certain sequence position certain certain certain sequence position certain vibha Vibrio harveyi 3 unspecified role unspecified role neutral component neutral component region Periplasmic domain sufficient to bind sufficient binding region sufficient to bind certain certain sequence position certain certain certain sequence position certain certain certain sequence position certain certain certain sequence position certain vibha Vibrio harveyi direct interaction direct interaction we crystallized AI-2 bound LuxPQp, after first deleting five residues from the N terminus of LuxP (see above). Crystals were improved by deleting, from the termini of LuxQp, those residues that were poorly ordered in the previously determined AI-2-free LuxPQp crystal structure (Neiditch et al., 2005). The 2.3A� resolution structure (Figures 3A�3C) was determined using phases obtained by molecular replacement (see Experimental Procedures, as well as Table S1 in the Supplemental Data available with this article online). The structure indeed contains two similar LuxPQp complexes, 3 A-C, Table S1 The complex was found in the presence of autoinducer-2 (AI-2) (3A-METHYL-5,6-DIHYDRO-FURO[2,3-D][1,3,2]DIOXABOROLE- 2,2,6,6A-TETRAOL). AI-2 binding causes a major conformational change within LuxP, which in turn stabilizes a quaternary arrangement in which two LuxPQ monomers are asymmetrically associated. The LuxQ sequence used has a Gly-Ser at the start not found in the Uniprot sequence at this position. 2.34 A Rfree(%) 26.18 luxp-luxq-1 2 4 unspecified role unspecified role neutral component neutral component c-terminal sufficient to bind sufficient binding region sufficient to bind certain certain sequence position certain certain certain sequence position certain vibha Vibrio harveyi 3 unspecified role unspecified role neutral component neutral component region Periplasmic domain sufficient to bind sufficient binding region sufficient to bind certain certain sequence position certain certain certain sequence position certain vibha Vibrio harveyi direct interaction direct interaction After deleting five residues from the N terminus of LuxP, a modification shown to stabilize the AI-2 bound state in vivo (Neiditch et al., 2005), liganded LuxPQp displayed a hydrodynamic radius of 4.0 � 0.1 nm. The complex was found in the presence of autoinducer-2 (AI-2) (3A-METHYL-5,6-DIHYDRO-FURO[2,3-D][1,3,2]DIOXABOROLE- 2,2,6,6A-TETRAOL). AI-2 binding causes a major conformational change within LuxP, which in turn stabilizes a quaternary arrangement in which two LuxPQ monomers are asymmetrically associated. The LuxQ sequence used may have a Gly-Ser at the start not found in the Uniprot sequence at this position as the sequence used in the X-ray crystallography experiment does. It is indicated that deleting the 5 N-terminal residues of LuxP promoted dimerisation of LuxPQ monomers. luxp-luxq-2 2 3 unspecified role unspecified role neutral component neutral component region sufficient to bind sufficient binding region sufficient to bind certain certain sequence position certain certain certain sequence position certain vibha Vibrio harveyi 4 unspecified role unspecified role neutral component neutral component c-terminal periplasmic domain sufficient to bind sufficient binding region sufficient to bind certain certain sequence position certain certain certain sequence position certain vibha Vibrio harveyi direct interaction direct interaction It is indicated that both LuxPQ monomers and dimers were found in the presence of autoinducer-2 (AI-2) (3A-METHYL-5,6-DIHYDRO-FURO[2,3-D][1,3,2]DIOXABOROLE- 2,2,6,6A-TETRAOL). AI-2 binding causes a major conformational change within LuxP, which in turn stabilizes a quaternary arrangement in which two LuxPQ monomers are asymmetrically associated. The LuxQ sequence used may have a Gly-Ser at the start not found in the Uniprot sequence at this position as the sequence used in the X-ray crystallography experiment does. The hydrodynamic radius (RH), a measure of molecular size and shape, was 3.4 � 0.1 nm in the absence of AI-2 but increased to 3.8 � 0.1 nm in the presence of AI-2. While the RH of unliganded LuxPQp is in excellent agreement with calculations based on the crystal structure (Neiditch et al., 2005), the RH after AI-2 addition is significantly larger. The measured value (3.8 nm) is intermediate between those predicted for LuxPQp monomers (3.4 nm) and (LuxPQp)2 dimers ( 4.3 nm) and probably reflects an equilibrium mixture of monomers and dimers.