2 results for Conference poster, Investigation into the racemic X-ray structure of the antimicrobial protein snakin-1

  • Investigation into the racemic X-ray structure of the antimicrobial protein snakin-1

    Yeung, Ho; Yosaatmadja, Yuliana; Squire, Christopher; Harris, Paul; Baker, Edward; Brimble, Margaret (2015-10-22)

    Conference poster
    The University of Auckland Library

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  • Investigation into the racemic X-ray structure of the antimicrobial protein snakin-1

    Yeung, Ho; Yosaatmadja, Yuliana; Squire, Christopher; Harris, Paul; Baker, Edward; Brimble, Margaret (2015-08-31)

    Conference poster
    The University of Auckland Library

    Snakin-1 is a 63 residue antimicrobial protein originally isolated from potato (Solanum tuberosum).1 It is active against a number of bacterial and fungal phytopathogens such as Clavibacter michiganensis, Pseudomonas syringae and Fusarium solani. Snakin-1 is a member of the GASA (gibberellic acid stimulated in Arabidopsis)/snakin family and the mature protein consists of a GASA domain incorporating six intramolecular disulfide bonds.2 The amino acid sequences of these proteins do not correspond to any known structural motifs. GASA/snakin proteins are found in a variety of plant species and appear to be involved in a range of functions including cell elongation and cell division.2 Their expression profiles support these roles and are commonly linked to development.2 It has also been speculated that the 12 conserved cysteines in these proteins perform a role in redox regulation.2 We have recently completed the total chemical synthesis of native Snakin-1 and showed that its antimicrobial activity is comparable to that of the naturally occurring protein.3 In an attempt to understand how this small protein functions we have determined its threedimensional structure by X-ray crystallography using a quasi-racemic protein system.4 Phase information for structural determination was obtained by radiation-damage induced phasing.5 The structure of snakin-1 appears to be novel, different to known classes of cysteine-rich plant antimicrobial peptide. Its features include a large and distinctly electropositive loop that we speculate to be membrane targeting, and a two helix bundle which is a potential membrane-interacting feature able to disrupt the structural integrity of its target bacteria.

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