Staphylococcus aureus lipase (SAL), a triacylglycerol esterase, is an important virulence factor and may be a therapeutic target for infectious diseases. Herein, we determined the 3D structure of native SAL, the mutated S116A inactive form, and the inhibitor complex using the anti-obesity drug orlistat to aid in drug development. the determined crystal structures showed a typical α/β hydrolase motif with a dimeric form. Fatty acids bound near the active site in native SAL and inactive S116A mutant structures. We found that orlistat potently inhibits SAL activity, and it covalently bound to the catalytic Ser116 residue. This is the first report detailing orlistat-lipase binding. It provides structure-based information on the production of potent anti-SAL drugs and lipase inhibitors. these results also indicated that orlistat can be repositioned to treat bacterial diseases.Staphylococcus aureus (SA) can cause skin, throat, and digestive tract infections. SA is a native bacterium that resides in the nasal cavity, respiratory tract, and skin, and infection typically results in a localized collection of pus 1,2 . SA is related to several diseases and produces various types of pathogenic toxins 3 . Methicillin-resistant SA (MRSA) is one of the most well-known "super bugs, " which has developed resistance to almost all current antibiotics 4,5 . It is a common nosocomial infection that presents a serious risk to those with weak immune systems such as children and the elderly 6 . Identifying novel, effective drugs is of great importance for treating MRSA-related diseases.SA lipase (SAL, also known as glycerol ester hydrolase), a triacylglycerol esterase ( Fig. 1A), shows strong cytopathic activity in host cells 7 . SAL is a potential target of anti-SA drugs in skin diseases 8 . SAL degrades lipids, which attack pathogenic bacteria 9,10 . By reducing the effect of immune-responsive lipids, SA colonization increases on the skin surface or inside the body. It has also been reported that some inhibitors such as farnesol decrease SA production 11 . Recently, Chen et al. observed that SAL released by SA inhibits the activation of innate immune cells and interferes with the host immune system to affect innate immune recognition in the microbe 12 .SAL, an ester bond-hydrolyzing enzyme, is secreted in prepolypeptide form containing 690 amino acid residues and is processed into its mature form containing 394 amino acid residues. Its active site is composed of a typical catalytic triad including Ser116, Asp 307, and His349 residues, similar to other serine hydrolases.Very few specific SAL-related bacterial lipase inhibitors have been identified to date 10,11 ; tetracycline is a known inhibitor of Staphylococcus epidermidis lipase 13 . An example of a SAL inhibitor is farnesol, which is a competitive inhibitor 11 . However, this monoterpenoid weakly inhibits SAL (IC 50 value, 0.57 mM). These inhibitors were not so potent against SAL-related bacterial lipases. We screened various chemical libraries and discovered that the anti-obesity...

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Staphylococcus aureus lipase (SAL), a triacylglycerol esterase, is an important virulence factor in S. aureus and may be a therapeutic target for infectious diseases caused by S. aureus. For the purposes of anti-SAL drug development using structure-based drug design, X-ray crystallographic analysis of SAL overexpressed in Escherichia coli was performed. The recombinant protein was purified using a three-step protocol involving immobilized metal-affinity chromatography, cation-exchange chromatography and anion-exchange chromatography flowthrough methods, yielding 40 mg of protein per litre of bacterial culture. Crystals were obtained using the sitting-drop vapor-diffusion technique. Diffraction data to 3.0 Å resolution were collected on the BL44XU beamline at SPring-8 at the zinc peak of 1.2842 Å for SAD phasing. The crystals belonged to space group P422 or P422, with unit-cell parameters a = 131.0, b = 131.0, c = 250.6 Å, and are likely to contain four SAL molecules (408 residues) per asymmetric unit.

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Pd cluster seeds for a double-layered perpendicular magnetic recording medium composed of a Co/Pd multilayered film and a CoZrNb soft magnetic underlayer (SUL) were fabricated with an electrochemical treatment. By immersing the SUL into an aqueous PdCl 2 solution, the substitution of Pd for Co at the surface of the SUL took place, which was caused by the difference in electrochemical redox potential between Pd and Co. Uniformly distributed Pd clusters with 8 nm in diameter were successfully formed with the treatment for the optimized duration. Use of the Pd clusters as the seeds for deposition of the Co/Pd multilayered film increased the perpendicular coercivity and reduced the size of magnetic cluster of the film. These results suggested that the Pd cluster seeds led to the formation of magnetically isolated Co/Pd multilayered grains, improving the magnetic properties of Co/Pd multilayered film.Index Terms-Co/Pd multilayered film, electrochemical treatment, island structure, Pd cluster seeds.