ジャーナル: PLoS Genet / 年: 2019 タイトル: Protease-associated import systems are widespread in Gram-negative bacteria. 著者: Rhys Grinter / Pok Man Leung / Lakshmi C Wijeyewickrema / Dene Littler / Simone Beckham / Robert N Pike / Daniel Walker / Chris Greening / Trevor Lithgow / 要旨: Bacteria have evolved sophisticated uptake machineries in order to obtain the nutrients required for growth. Gram-negative plant pathogens of the genus Pectobacterium obtain iron from the protein ...Bacteria have evolved sophisticated uptake machineries in order to obtain the nutrients required for growth. Gram-negative plant pathogens of the genus Pectobacterium obtain iron from the protein ferredoxin, which is produced by their plant hosts. This iron-piracy is mediated by the ferredoxin uptake system (Fus), a gene cluster encoding proteins that transport ferredoxin into the bacterial cell and process it proteolytically. In this work we show that gene clusters related to the Fus are widespread in bacterial species. Through structural and biochemical characterisation of the distantly related Fus homologues YddB and PqqL from Escherichia coli, we show that these proteins are analogous to components of the Fus from Pectobacterium. The membrane protein YddB shares common structural features with the outer membrane ferredoxin transporter FusA, including a large extracellular substrate binding site. PqqL is an active protease with an analogous periplasmic localisation and iron-dependent expression to the ferredoxin processing protease FusC. Structural analysis demonstrates that PqqL and FusC share specific features that distinguish them from other members of the M16 protease family. Taken together, these data provide evidence that protease associated import systems analogous to the Fus are widespread in Gram-negative bacteria.
This domain of PqqL was crystallised by in situ Trypsination of the full-length protein. This was ...This domain of PqqL was crystallised by in situ Trypsination of the full-length protein. This was the sequence of the purified protein that was added to the drop (With a small quantity of Trypsin): AALPQDEKLITGQLDNGLRYMIYPHAHPKDQVNLWLQIHTGSLQEEDNELGVAHFVEHMMFNGTKTWPGNKVIETFESMGLRFGRDVNAYTSYDETVYQVSLPTTQKQNLQQVMAIFSEWSNAATFEKLEVDAERGVITEEWRAHQDAKWRTSQARRPFLLANTRNLDREPIGLMDTVATVTPAQLRQFYQRWYQPNNMTFIVVGDIDSKEALALIKDNLSKLPANKAAENRVWPTKAENHLRFNIINDKENRVNGIALYYRLPMVQVNDEQSFIEQAEWSMLVQLFNQRLQERIQSGELKTISGGTARSVKIAPDYQSLFFRVNARDDNMQDAANALMAELATIDQHGFSAEELDDVKSTRLTWLKNAVDQQAERDLRMLTSRLASSSLNNTPFLSPEETYQLSKRLWQQITVQSLAEKWQQLRKNQDAFWEQMVNNEVAAKKALSPAAILALEKEYANKKLAAYVFPGRNLSLTVDADPQAEISSKETLAENLTSLTLSNGARVILAKSAGEEQKLQIIAVSNKGDLSFPAQQKSLIALANKAVSGSGVGELSSSSLKRWSAENSVTMSSKVSGMNTLLSVSARTNNPEPGFQLINQRITHSTINDNIWASLQNAQIQALKTLDQRPAEKFAQQMYETRYADDRTKLLQENQIAQFTAADALAADRQLFSSPADITFVIVGNVAEDKLVALITRYLGSIKHSDSPLAAGKPLTRATDNASVTVKEQNEPVAQVSQWKRYDSRTPVNLPTRMALDAFNVALAKDLRVNIREQASGAYSVSSRLSVDPQAKDISHLLAFTCQPERHDELLTLANEVMVKRLAKGISEQELNEYQQNVQRSLDIQQRSVQQLANTIVNSLIQYDDPAAWTEQEQLLKQMTVENVNTAVKQYLSHPVNTYTGVLLPKLEHHHHHH The most likely cleavage point for Trypsin is ARG497, meaning the protein in the crystal consists of the first 497 amino acids, minus the first 26 amino acids as reported.