| Id |
Subject |
Object |
Predicate |
Lexical cue |
| T1 |
0-115 |
Sentence |
denotes |
Heme is an effector molecule for iron-dependent degradation of the bacterial iron response regulator (Irr) protein. |
| T2 |
116-224 |
Sentence |
denotes |
The bacterial iron response regulator (Irr) protein mediates iron-dependent regulation of heme biosynthesis. |
| T3 |
225-451 |
Sentence |
denotes |
Pulse-chase and immunoprecipitation experiments showed that Irr degraded in response to 6 microM iron with a half-life of approximately 30 min and that this regulated stability was the principal determinant of control by iron. |
| T4 |
452-519 |
Sentence |
denotes |
Irr contains a heme regulatory motif (HRM) near its amino terminus. |
| T5 |
520-639 |
Sentence |
denotes |
A role for heme in regulation was implicated by the retention of Irr in heme synthesis mutants in the presence of iron. |
| T6 |
640-785 |
Sentence |
denotes |
Addition of heme to low iron (0.3 microM) cultures was sufficient for the disappearance of Irr in cells of the wild-type and heme mutant strains. |
| T7 |
786-981 |
Sentence |
denotes |
Spectral and binding analyses of purified recombinant Irr showed that the protein bound heme with high affinity and caused a blue shift in the absorption spectrum of heme to a shorter wavelength. |
| T8 |
982-1118 |
Sentence |
denotes |
A Cys(29) --> Ala substitution within the HRM of Irr (IrrC29A) abrogated both high affinity binding to heme and the spectral blue shift. |
| T9 |
1119-1226 |
Sentence |
denotes |
In vivo turnover experiments showed that, unlike wild-type Irr, IrrC29A was stable in the presence of iron. |
| T10 |
1227-1336 |
Sentence |
denotes |
We conclude that iron-dependent degradation of Irr involves direct binding of heme to the protein at the HRM. |
| T11 |
1337-1475 |
Sentence |
denotes |
The findings implicate a regulatory role for heme in protein degradation and provide direct evidence for a functional HRM in a prokaryote. |
