{"id":{"repo_id":"uiuc","oai_identifier":"oai:www.ideals.illinois.edu:2142/78752"},"canonical_url":"https://search.dev.ndltd.org/etd/uiuc/oai:www.ideals.illinois.edu:2142/78752","repository":{"repo_id":"uiuc","name":"University of Illinois - Urbana-Champaign","base_url":"https://www.ideals.illinois.edu/oai-pmh"},"display":{"title":"Mechanistic studies of lanthipeptide biosynthesis","abstract":"Natural products and natural product derivatives have been the leading source of pharmaceutical compounds since the initial application of modern medicine. To fight the increasing occurrence of drug resistance and to reach the ultimate goal of personalized drugs for treating complicated symptoms, novel natural products are demanded. Lanthipeptides are ribosomal peptides with post-translationally incorporated thioether crosslinks named lanthionine. This family of natural products has garnered substantial attention during the past few decades due to their favorable biological activities and the potential for engineering. This thesis focuses on a subclass of lanthipeptides, the class II compounds, for which the synthesis of dehydroamino acids and the formation of thioether linkages are carried out by a bifunctional lanthionine synthetase. Chapter 2 presents the structural characterization of the enterococcal cytolysin, a lanthipeptide tightly linked to Enterococcus faecalis virulence. The stereoselectivity of lanthionine synthesis is discussed in chapters 3 and 4. A non-canonical configuration of lanthionines was discovered in a few lanthipeptides and the selective synthesis of the unusual stereochemistry was found to be induced by the peptide sequence rather than the lanthionine synthetase. Such a substrate-controlled stereoselectivity is rarely identified in naturally occurring enzymatic processes. Although it has been more than ten years since the first in vitro reconstitution of a class II lanthionine synthetase, no structural information was available for this class of proteins before the study presented in chapter 5 with respect to the cytolysin synthetase CylM. Unexpectedly, the CylM dehydratase domain resembles the catalytic core of lipid kinases despite the absence of notable sequence homology. Mutagenesis study of CylM provides further insights into the mechanism of the modification process. The maturation of lanthipeptides typically requires a proteolytic step that removes the leader peptide from the modified precursor peptides. Characterization of two peptidases involved in the synthesis of lichenicidin and cytolysin, described in chapters 6 and 7, provides mechanistic insights into these subtilisin-like proteins and reveals their potential as sequence-specific proteases. In addition, structural elucidation of four prochlorosins, a set of lanthipeptides synthesized by a highly substrate-tolerant synthetase ProcM in marine bacteria, is included as chapter 8. The unveiled structural information of these lanthipeptides and the biochemical studies with respect to the biosynthetic process described in this thesis may assist the genome mining and synthetic biology efforts towards novel lanthipeptides for therapeutic purposes and other applications.","abstract_html":"Natural products and natural product derivatives have been the leading source of pharmaceutical compounds since the initial application of modern medicine. To fight the increasing occurrence of drug resistance and to reach the ultimate goal of personalized drugs for treating complicated symptoms, novel natural products are demanded. Lanthipeptides are ribosomal peptides with post-translationally incorporated thioether crosslinks named lanthionine. This family of natural products has garnered substantial attention during the past few decades due to their favorable biological activities and the potential for engineering. This thesis focuses on a subclass of lanthipeptides, the class II compounds, for which the synthesis of dehydroamino acids and the formation of thioether linkages are carried out by a bifunctional lanthionine synthetase. Chapter 2 presents the structural characterization of the enterococcal cytolysin, a lanthipeptide tightly linked to Enterococcus faecalis virulence. The stereoselectivity of lanthionine synthesis is discussed in chapters 3 and 4. A non-canonical configuration of lanthionines was discovered in a few lanthipeptides and the selective synthesis of the unusual stereochemistry was found to be induced by the peptide sequence rather than the lanthionine synthetase. Such a substrate-controlled stereoselectivity is rarely identified in naturally occurring enzymatic processes. Although it has been more than ten years since the first in vitro reconstitution of a class II lanthionine synthetase, no structural information was available for this class of proteins before the study presented in chapter 5 with respect to the cytolysin synthetase CylM. Unexpectedly, the CylM dehydratase domain resembles the catalytic core of lipid kinases despite the absence of notable sequence homology. Mutagenesis study of CylM provides further insights into the mechanism of the modification process. The maturation of lanthipeptides typically requires a proteolytic step that removes the leader peptide from the modified precursor peptides. Characterization of two peptidases involved in the synthesis of lichenicidin and cytolysin, described in chapters 6 and 7, provides mechanistic insights into these subtilisin-like proteins and reveals their potential as sequence-specific proteases. In addition, structural elucidation of four prochlorosins, a set of lanthipeptides synthesized by a highly substrate-tolerant synthetase ProcM in marine bacteria, is included as chapter 8. The unveiled structural information of these lanthipeptides and the biochemical studies with respect to the biosynthetic process described in this thesis may assist the genome mining and synthetic biology efforts towards novel lanthipeptides for therapeutic purposes and other applications.","abstract_has_math":false,"creators":["Tang, Weixin"],"institution":"University of Illinois at Urbana-Champaign","degree_name":"Ph.D.","degree_level":"Dissertation","degree_discipline":"Chemistry","degree_department":null,"school":null,"contributors":["van der Donk, Wilfred A.","Nair, Satish K.","Rienstra, Chad M.","Zhao, Huimin"],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2015,"date_issued":"2015-07-22T22:45:33Z","date_published":"2015-07-22T22:45:33Z","updated_at":"2026-07-22T22:26:12Z","subjects":["Enzyme mechanism","Lanthipeptide"],"languages":["en"],"rights":["copyright 2015 Weixin Tang"],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"http://hdl.handle.net/2142/78752","outbound_label":"Handle","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["van der Donk, Wilfred A.","Nair, Satish K.","Rienstra, Chad M.","Zhao, Huimin"]},{"key":"dc:creator","label":"Author","values":["Tang, Weixin"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2015-07-22T22:45:33Z","2017-07-23T09:15:21Z","2015-05","2015-04-22","2015-5"]},{"key":"dc:type","label":"Dc Type","values":["text"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Chemistry"]},{"key":"thesis:degree_level","label":"Degree Level","values":["Dissertation"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Ph.D."]},{"key":"thesis:institution_name","label":"Thesis Institution Name","values":["University of Illinois at Urbana-Champaign"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Enzyme mechanism","Lanthipeptide"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["en"]},{"key":"dc:rights","label":"Dc Rights","values":["copyright 2015 Weixin Tang"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["http://hdl.handle.net/2142/78752"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["Natural products and natural product derivatives have been the leading source of pharmaceutical compounds since the initial application of modern medicine. To fight the increasing occurrence of drug resistance and to reach the ultimate goal of personalized drugs for treating complicated symptoms, novel natural products are demanded. Lanthipeptides are ribosomal peptides with post-translationally incorporated thioether crosslinks named lanthionine. This family of natural products has garnered substantial attention during the past few decades due to their favorable biological activities and the potential for engineering. This thesis focuses on a subclass of lanthipeptides, the class II compounds, for which the synthesis of dehydroamino acids and the formation of thioether linkages are carried out by a bifunctional lanthionine synthetase. Chapter 2 presents the structural characterization of the enterococcal cytolysin, a lanthipeptide tightly linked to Enterococcus faecalis virulence. The stereoselectivity of lanthionine synthesis is discussed in chapters 3 and 4. A non-canonical configuration of lanthionines was discovered in a few lanthipeptides and the selective synthesis of the unusual stereochemistry was found to be induced by the peptide sequence rather than the lanthionine synthetase. Such a substrate-controlled stereoselectivity is rarely identified in naturally occurring enzymatic processes. Although it has been more than ten years since the first in vitro reconstitution of a class II lanthionine synthetase, no structural information was available for this class of proteins before the study presented in chapter 5 with respect to the cytolysin synthetase CylM. Unexpectedly, the CylM dehydratase domain resembles the catalytic core of lipid kinases despite the absence of notable sequence homology. Mutagenesis study of CylM provides further insights into the mechanism of the modification process. The maturation of lanthipeptides typically requires a proteolytic step that removes the leader peptide from the modified precursor peptides. Characterization of two peptidases involved in the synthesis of lichenicidin and cytolysin, described in chapters 6 and 7, provides mechanistic insights into these subtilisin-like proteins and reveals their potential as sequence-specific proteases. In addition, structural elucidation of four prochlorosins, a set of lanthipeptides synthesized by a highly substrate-tolerant synthetase ProcM in marine bacteria, is included as chapter 8. The unveiled structural information of these lanthipeptides and the biochemical studies with respect to the biosynthetic process described in this thesis may assist the genome mining and synthetic biology efforts towards novel lanthipeptides for therapeutic purposes and other applications.","Submission published under a 24 month embargo labeled 'Closed Access', the embargo will last until 2017-05-01","The student, Weixin Tang, accepted the attached license on 2015-04-19 at 14:00.","The student, Weixin Tang, submitted this Dissertation for approval on 2015-04-19 at 14:08.","This Dissertation was approved for publication on 2015-04-22 at 07:40.","DSpace SAF Submission Ingestion Package generated from Vireo submission #7937 on 2015-07-22 at 14:25:26","Made available in DSpace on 2015-07-22T22:45:33Z (GMT). No. of bitstreams: 2 TANG-DISSERTATION-2015.pdf: 12303720 bytes, checksum: 7481b08e7bb9657ba8dfc20cb3717360 (MD5) LICENSE.txt: 4208 bytes, checksum: 39116b77986f96ffe892894a4050e884 (MD5) Previous issue date: 2015-04-22","Embargo set by: Seth Robbins for item 79993 Lift date: 2017-07-22T22:46:21Z Reason: Author requested closed access (OA after 2yrs) in Vireo ETD system","Limited Restriction Lifted for Item 79993 on 2017-07-23T09:15:21Z."]},{"key":"dc:format","label":"Dc Format","values":["application/pdf"]},{"key":"dc:title","label":"Title","values":["Mechanistic studies of lanthipeptide biosynthesis"]}]}],"canonical_facts":{"dc:contributor":["van der Donk, Wilfred A.","Nair, Satish K.","Rienstra, Chad M.","Zhao, Huimin"],"dc:creator":["Tang, Weixin"],"dc:date":["2015-07-22T22:45:33Z","2017-07-23T09:15:21Z","2015-05","2015-04-22","2015-5"],"dc:description":["Natural products and natural product derivatives have been the leading source of pharmaceutical compounds since the initial application of modern medicine. To fight the increasing occurrence of drug resistance and to reach the ultimate goal of personalized drugs for treating complicated symptoms, novel natural products are demanded. Lanthipeptides are ribosomal peptides with post-translationally incorporated thioether crosslinks named lanthionine. This family of natural products has garnered substantial attention during the past few decades due to their favorable biological activities and the potential for engineering. This thesis focuses on a subclass of lanthipeptides, the class II compounds, for which the synthesis of dehydroamino acids and the formation of thioether linkages are carried out by a bifunctional lanthionine synthetase. Chapter 2 presents the structural characterization of the enterococcal cytolysin, a lanthipeptide tightly linked to Enterococcus faecalis virulence. The stereoselectivity of lanthionine synthesis is discussed in chapters 3 and 4. A non-canonical configuration of lanthionines was discovered in a few lanthipeptides and the selective synthesis of the unusual stereochemistry was found to be induced by the peptide sequence rather than the lanthionine synthetase. Such a substrate-controlled stereoselectivity is rarely identified in naturally occurring enzymatic processes. Although it has been more than ten years since the first in vitro reconstitution of a class II lanthionine synthetase, no structural information was available for this class of proteins before the study presented in chapter 5 with respect to the cytolysin synthetase CylM. Unexpectedly, the CylM dehydratase domain resembles the catalytic core of lipid kinases despite the absence of notable sequence homology. Mutagenesis study of CylM provides further insights into the mechanism of the modification process. The maturation of lanthipeptides typically requires a proteolytic step that removes the leader peptide from the modified precursor peptides. Characterization of two peptidases involved in the synthesis of lichenicidin and cytolysin, described in chapters 6 and 7, provides mechanistic insights into these subtilisin-like proteins and reveals their potential as sequence-specific proteases. In addition, structural elucidation of four prochlorosins, a set of lanthipeptides synthesized by a highly substrate-tolerant synthetase ProcM in marine bacteria, is included as chapter 8. The unveiled structural information of these lanthipeptides and the biochemical studies with respect to the biosynthetic process described in this thesis may assist the genome mining and synthetic biology efforts towards novel lanthipeptides for therapeutic purposes and other applications.","Submission published under a 24 month embargo labeled 'Closed Access', the embargo will last until 2017-05-01","The student, Weixin Tang, accepted the attached license on 2015-04-19 at 14:00.","The student, Weixin Tang, submitted this Dissertation for approval on 2015-04-19 at 14:08.","This Dissertation was approved for publication on 2015-04-22 at 07:40.","DSpace SAF Submission Ingestion Package generated from Vireo submission #7937 on 2015-07-22 at 14:25:26","Made available in DSpace on 2015-07-22T22:45:33Z (GMT). No. of bitstreams: 2 TANG-DISSERTATION-2015.pdf: 12303720 bytes, checksum: 7481b08e7bb9657ba8dfc20cb3717360 (MD5) LICENSE.txt: 4208 bytes, checksum: 39116b77986f96ffe892894a4050e884 (MD5) Previous issue date: 2015-04-22","Embargo set by: Seth Robbins for item 79993 Lift date: 2017-07-22T22:46:21Z Reason: Author requested closed access (OA after 2yrs) in Vireo ETD system","Limited Restriction Lifted for Item 79993 on 2017-07-23T09:15:21Z."],"dc:format":["application/pdf"],"dc:identifier":["http://hdl.handle.net/2142/78752"],"dc:language":["en"],"dc:rights":["copyright 2015 Weixin Tang"],"dc:subject":["Enzyme mechanism","Lanthipeptide"],"dc:title":["Mechanistic studies of lanthipeptide biosynthesis"],"dc:type":["text"],"thesis:degree_discipline":["Chemistry"],"thesis:degree_level":["Dissertation"],"thesis:degree_name":["Ph.D."],"thesis:institution_name":["University of Illinois at Urbana-Champaign"]},"updated_at":"2026-07-22T22:26:12Z"}