Editing Lysozyme (section)

== Other applications ==
Lysozyme crystals have been used to grow other functional materials for catalysis and biomedical applications.<ref>{{cite journal | vauthors = Wei H, Wang Z, Zhang J, House S, Gao YG, Yang L, Robinson H, Tan LH, Xing H, Hou C, Robertson IM, Zuo JM, Lu Y | title = Time-dependent, protein-directed growth of gold nanoparticles within a single crystal of lysozyme | journal = Nature Nanotechnology | volume = 6 | issue = 2 | pages = 93–97 | date = February 2011 | pmid = 21278750 | doi = 10.1038/nnano.2010.280 | bibcode = 2011NatNa...6...93W }}</ref><ref>{{cite journal | vauthors = Sanghamitra NJ, Ueno T | title = Expanding coordination chemistry from protein to protein assembly | journal = Chemical Communications | volume = 49 | issue = 39 | pages = 4114–4126 | date = May 2013 | pmid = 23211931 | doi = 10.1039/C2CC36935D }}</ref><ref>{{cite journal | vauthors = Ueno T | title = Porous protein crystals as reaction vessels | journal = Chemistry: A European Journal | volume = 19 | issue = 28 | pages = 9096–9102 | date = July 2013 | pmid = 23813903 | doi = 10.1002/chem.201300250 }}</ref> Lysozyme is a commonly used enzyme for lysing gram positive bacteria.<ref>{{cite journal | vauthors = Repaske R | title = Lysis of gram-negative bacteria by lysozyme | journal = Biochimica et Biophysica Acta | volume = 22 | issue = 1 | pages = 189–191 | date = October 1956 | pmid = 13373865 | doi = 10.1016/0006-3002(56)90240-2 }}</ref> Due to the unique function of lysozyme in which it can digest the cell wall and causes [[osmotic shock]] (burst the cell by suddenly changing solute concentration around the cell and thus the [[osmotic pressure]]), lysozyme is commonly used in lab setting to release proteins from bacterium [[periplasm]] while the inner membrane remains sealed as vesicles called the [[spheroplast]].<ref>{{Cite book|title=Protein Condensation : Kinetic Pathways to Crystallization and Disease |url= https://archive.org/details/proteincondensat00gunt|url-access=limited| vauthors = Gunton J, Shiryayev A, Pagan DL |location = Cambridge | publisher = Cambridge University Press |year=2007 |isbn= 978-0-511-53532-1 |pages=[https://archive.org/details/proteincondensat00gunt/page/n168 156]–158}}</ref><ref>{{Cite book|title=Fundamental Laboratory Approaches for Biochemistry and Biotechnology | vauthors = Ninfa A, Ballou D, Benore M |publisher=John Wiley |year=2010 |isbn=978-0-470-08766-4 }}</ref>

For example, ''E. coli'' can be lysed using lysozyme to free the contents of the [[periplasm]]ic space. It is especially useful in lab setting for trying to collect the contents of the periplasm.<ref name=":0" /> Lysozyme treatment is optimal at particular temperatures, pH ranges, and salt concentrations. Lysozyme activity increases with increasing temperatures, up to 60 degrees Celsius, with a pH range of 6.0-7.0. The salts present also affect lysozyme treatment, where some assert inhibitory effects, and others promote lysis via lysozyme treatment. Sodium chloride induces lysis, but at high concentrations, it is an active inhibitor of lysis. Similar observations have been seen with the use of potassium salts. Slight variations are present due to differences in bacterial strains.<ref>{{cite journal | vauthors = Salton MR | title = The properties of lysozyme and its action on microorganisms | journal = Bacteriological Reviews | volume = 21 | issue = 2 | pages = 82–100 | date = June 1957 | pmid = 13436356 | pmc = 180888 | doi = 10.1128/MMBR.21.2.82-100.1957 }}</ref> A consequence of the use of lysozyme in extracting recombinant proteins for [[protein crystallization]] is that the crystal may be contaminated with units of lysozyme, producing a physiologically irrelevant combination. In fact, some proteins simply cannot crystalize without such contamination.<ref>{{cite journal | vauthors = Liu W, MacGrath SM, Koleske AJ, Boggon TJ | title = Lysozyme contamination facilitates crystallization of a heterotrimeric cortactin-Arg-lysozyme complex | journal = Acta Crystallographica. Section F, Structural Biology and Crystallization Communications | volume = 68 | issue = Pt 2 | pages = 154–158 | date = February 2012 | pmid = 22297987 | pmc = 3274391 | doi = 10.1107/S1744309111056132 }}</ref><ref>{{cite journal | vauthors = Kincannon WM, Zahn M, Clare R, Lusty Beech J, Romberg A, Larson J, Bothner B, Beckham GT, McGeehan JE, DuBois JL | title = Biochemical and structural characterization of an aromatic ring-hydroxylating dioxygenase for terephthalic acid catabolism | journal = Proceedings of the National Academy of Sciences of the United States of America | volume = 119 | issue = 13 | pages = e2121426119 | date = March 2022 | pmid = 35312352 | pmc = 9060491 | doi = 10.1073/pnas.2121426119 | doi-access = free | bibcode = 2022PNAS..11921426K }}</ref>

Furthermore, lysozyme can serve as a tool in the expression of toxic recombinant proteins. Expressing recombinant proteins in BL21(DE3) strains is typically accomplished by the T7-RNA-polymerase. Via IPTG induction, the UV-5 repressor is inhibited, leading to the transcription of the T7-RNA-polymerase and thereby of the protein of interest. Nonetheless, a basal level of the T7-RNA-polymerase is observable even without induction. T7 lysozyme acts as an inhibitor of the T7-RNA-polymerase. Newly invented strains, containing a helper plasmid (pLysS), constitutively co-express low levels of T7 lysozyme, providing high stringency and consistent expression of the toxic recombinant protein.<ref>{{cite journal | vauthors = Pan SH, Malcolm BA | title = Reduced background expression and improved plasmid stability with pET vectors in BL21 (DE3) | journal = BioTechniques | volume = 29 | issue = 6 | pages = 1234–1238 | date = December 2000 | pmid = 11126126 | doi = 10.2144/00296st03 | doi-access = free }}</ref>