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SUMMARY:Experimental estimation of copper-ligand length precision in a mod
 el fungal LPMO under redox cycling and saccharide binding
DTSTART;VALUE=DATE-TIME:20250922T165000Z
DTEND;VALUE=DATE-TIME:20250922T170000Z
DTSTAMP;VALUE=DATE-TIME:20260526T034238Z
UID:indico-contribution-1840@lindico453.srv.lu.se
DESCRIPTION:Speakers: Zhiyu Huang (University of Copenhagen)\nLytic polysa
 ccharide monooxygenases (LPMOs) are copper-dependent enzymes that degrade 
 polysaccharides oxidatively\, with applications in second-generation bioet
 hanol production and as virulence factors in certain pathogens [1] [2]. Th
 ey have been reclassified within the CAZy database into auxiliary activity
  families AA9–AA11 and AA13–AA17 [3]\, and their active-site histidine
  brace is highly conserved. The catalytic mechanism of LPMOs is complex\, 
 with the priming reaction step requiring the reduction of Cu(II) to Cu(I).
  Since the geometric changes associated with redox cycling—whether chemi
 cally induced or triggered by photoreduction—can be subtle\, the accurat
 e determination of bond lengths and angles is essential [4]. In this study
 \, LsAA9A from Lentinus similis was used as a model system under various e
 xperimental conditions. Analysis of the LsAA9A_Ec and LsAA9A_Ec_Cell3 stru
 ctures collected under low-dose conditions showed that\, compared with oth
 er Cu-coordination distances\, only the Tyr–Cu bond exhibited a statisti
 cally significant change (p = 0.00094 in two tailed t-test). These finding
 s confirm that saccharide substrate binding consistently shortens the Tyr
 –Cu distance in LsAA9A_Ec in the Cu²⁺ state\, with a measured reducti
 on of 0.21 Å. Furthermore\, experiments on LsAA9A_Ec_Asc and LsAA9A_Ec_As
 c_Cell3\, conducted under both low- and high-dose conditions\, where Cu²
 ⁺ can be reduced to Cu⁺ by X-ray exposure\, as well as at room tempera
 ture\, further probed structural responses to varying redox and experiment
 al regimes. These findings advance the mechanistic understanding of LPMOs 
 and offer a framework for probing subtle geometric changes in metalloenzym
 es.\n\nAuthors: Zhiyu Huang\, Jie Nan\, Monika Bjelcic\, Leila Lo Leggio\n
 \nhttps://lindico453.srv.lu.se/event/583/contributions/1840/
LOCATION:LINXS at The Loop
URL:https://lindico453.srv.lu.se/event/583/contributions/1840/
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