A PHP Error was encountered

Severity: Warning

Message: file_get_contents(https://...@gmail.com&api_key=61f08fa0b96a73de8c900d749fcb997acc09): Failed to open stream: HTTP request failed! HTTP/1.1 429 Too Many Requests

Filename: helpers/my_audit_helper.php

Line Number: 143

Backtrace:

File: /var/www/html/application/helpers/my_audit_helper.php
Line: 143
Function: file_get_contents

File: /var/www/html/application/helpers/my_audit_helper.php
Line: 209
Function: simplexml_load_file_from_url

File: /var/www/html/application/helpers/my_audit_helper.php
Line: 3098
Function: getPubMedXML

File: /var/www/html/application/controllers/Detail.php
Line: 574
Function: pubMedSearch_Global

File: /var/www/html/application/controllers/Detail.php
Line: 488
Function: pubMedGetRelatedKeyword

File: /var/www/html/index.php
Line: 316
Function: require_once

A PHP Error was encountered

Severity: Warning

Message: Attempt to read property "Count" on bool

Filename: helpers/my_audit_helper.php

Line Number: 3100

Backtrace:

File: /var/www/html/application/helpers/my_audit_helper.php
Line: 3100
Function: _error_handler

File: /var/www/html/application/controllers/Detail.php
Line: 574
Function: pubMedSearch_Global

File: /var/www/html/application/controllers/Detail.php
Line: 488
Function: pubMedGetRelatedKeyword

File: /var/www/html/index.php
Line: 316
Function: require_once

The carbohydrate tail of landomycin A is responsible for its interaction with the repressor protein LanK. | LitMetric

AI Article Synopsis

  • Landomycin A (LaA) is a potent anticancer compound produced by Streptomyces cyanogenus S136, which has a unique structure that intrigues scientists.
  • LanK is a regulatory protein that controls the release of LaA, ensuring it is only exported once enough of the product has accumulated.
  • Recent findings reveal that LanK specifically senses the carbohydrate components of LaA to trigger its own action, marking it as a unique type of TetR repressor that operates differently from other known repressors in natural product biosynthesis.

Article Abstract

Landomycin A (LaA) is the largest member of the landomycin group of angucyclic polyketides. Its unusual structure and strong anticancer properties have attracted great interest from chemists and biologists alike. This, in particular, has led to a detailed picture of LaA biosynthesis in Streptomyces cyanogenus S136, the only known LaA producer. LanK is a TetR family repressor protein that limits the export of landomycins from S136 cells until significant amounts of the final product, LaA, have accumulated. Landomycins carrying three or more carbohydrate units in their glycosidic chain are effector molecules for LanK. Yet, the exact mechanism that LanK uses to distinguish the final product, LaA, from intermediate landomycins and sense accumulation of LaA was not known. Here, we report crystal structures of LanK, alone and in complex with LaA, and bioassays of LanK's interaction with synthetic carbohydrate chains of LaA (hexasaccharide) and LaE (trisaccharide). Our data collectively suggest that the carbohydrate moieties are the sole determinants of the interaction of the landomycins with LanK, triggering the latter's dissociation from the lanK-lanJ intergenic region via structure conversion of the helices in the C-terminal ligand-binding domain. Analysis of the available literature suggests that LanK represents an unprecedented type of TetR family repressor that recognises the carbohydrate portion of a natural product, and not an aglycon, as it is the case, for example, with the SimR repressor involved in simocyclinone biosynthesis.

Download full-text PDF

Source
http://dx.doi.org/10.1111/febs.16460DOI Listing

Publication Analysis

Top Keywords

repressor protein
8
laa
8
tetr family
8
family repressor
8
final product
8
product laa
8
lank
7
carbohydrate
5
carbohydrate tail
4
tail landomycin
4

Similar Publications

Want AI Summaries of new PubMed Abstracts delivered to your In-box?

Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!

A PHP Error was encountered

Severity: Notice

Message: fwrite(): Write of 34 bytes failed with errno=28 No space left on device

Filename: drivers/Session_files_driver.php

Line Number: 272

Backtrace:

A PHP Error was encountered

Severity: Warning

Message: session_write_close(): Failed to write session data using user defined save handler. (session.save_path: /var/lib/php/sessions)

Filename: Unknown

Line Number: 0

Backtrace: