PXD017538

PXD017538 is an original dataset announced via ProteomeXchange.

Title	The heme regulatory motifs of heme oxygenase-2 function to transfer heme to the catalytic site for degradation
Description	Heme regulatory motifs (HRMs) are found in a variety of proteins that are involved in diverse biological functions. In the C-terminal tail region of human heme oxygenase-2 (HO2), there are two HRMs whose cysteines form a disulfide bond; when reduced, these cysteines are available to bind Fe3+-heme. Heme binding to the HRMs is independent of the HO2 catalytic active site in the core of the protein, where heme binds with high affinity and is degraded to biliverdin. Here, we describe the reversible, protein-mediated transfer of heme between the HRMs and the core of HO2. Using HDX-MS to monitor the dynamics of HO2 with and without Fe3+-heme bound to the HRMs and to the core, we detected conformational changes in the catalytic core only in one state of the catalytic cycle – when Fe3+-heme is bound to the HRMs and the core is in the apo state. The conformational changes detected are consistent with transfer of heme between binding sites. Indeed, Fe3+-heme bound to the HRMs is transferred to the apo-core upon either independently expressing the core and a construct spanning the HRM-containing tail or after single turnover of heme at the core. In addition, we observed transfer of heme from the core to the HRMs and equilibration of heme between the core and HRMs. We thus propose a Fe3+-heme transfer model in which heme bound to the HRMs is readily transferred to the catalytic site for degradation to facilitate turnover but can also equilibrate between the sites to maintain heme homeostasis.
HostingRepository	PRIDE
AnnounceDate	2020-03-18
AnnouncementXML	Submission_2020-03-18_05:19:20.xml
DigitalObjectIdentifier
ReviewLevel	Peer-reviewed dataset
DatasetOrigin	Original dataset
RepositorySupport	Unsupported dataset by repository
PrimarySubmitter	John R. Engen
SpeciesList	scientific name: Homo sapiens (Human); NCBI TaxID: 9606;
ModificationList	No PTMs are included in the dataset
Instrument	Synapt MS

Revision	Datetime	Status	ChangeLog Entry
0	2020-02-17 03:04:54	ID requested
⏵ 1	2020-03-18 05:19:21	announced

Fleischhacker AS, Gunawan AL, Kochert BA, Liu L, Wales TE, Borowy MC, Engen JR, Ragsdale SW, The heme-regulatory motifs of heme oxygenase-2 contribute to the transfer of heme to the catalytic site for degradation. J Biol Chem, 295(16):5177-5191(2020) [pubmed]

submitter keyword: enzyme mechanisms

enzyme kinetics

protein dynamics

conformational change

hydrogen deuterium exchange

HDXMS

John R Engen
contact affiliation	Department of Chemistry & Chemical biology, Northeastern University
contact email	j.engen@northeastern.edu
lab head
John R. Engen
contact affiliation	Northeastern University
contact email	j.engen@northeastern.edu
dataset submitter

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PRIDE project URI

• PRIDE
  1. PXD017538
     1. Label: PRIDE project
     2. Name: The heme regulatory motifs of heme oxygenase-2 function to transfer heme to the catalytic site for degradation