PR-39

CHEBI:131850 ·resolve ·ANTIBACTERIAL ·EXACT REVIEWED

A 39 amino acid porcine cathelicidin that is rich in proline and arginine residues. It plays a pivotal role in the innate immune defence of the pig against infections and exhibits antimicrobial and immunomodulatory activities. — ChEBI

Classification

Strictly broader compounds or drug classes this molecule belongs to.

cathelicidin CHEBI:81578

Chemical structure

Computed structure properties
Molecular formula	C229H345N69O41
Charge	0
Average mass	4720.721 Da
Monoisotopic mass	4717.70324 Da
Source	ChEBI
InChIKey	JTJJGVCUEGCBHL-IWDHFESKSA-N

SMILES

CC[C@H](C)[C@H](NC(=O)[C@H](CCCNC(=N)N)NC(=O)[C@@H]1CCCN1C(=O)[C@@H]1CCCN1C(=O)[C@H](CC(C)C)NC(=O)[C@H](CCCNC(=N)N)NC(=O)[C@@H]1CCCN1C(=O)[C@@H]1CCCN1C(=O)[C@H](Cc1ccccc1)NC(=O)[C@H](Cc1ccccc1)NC(=O)[C@@H]1CCCN1C(=O)[C@@H]1CCCN1C(=O)[C@@H]1CCCN1C(=O)[C@H](CCCNC(=N)N)NC(=O)[C@@H]1CCCN1C(=O)[C@H](CCCNC(=N)N)NC(=O)[C@@H]1CCCN1C(=O)[C@H](CC(C)C)NC(=O)[C@H](Cc1ccc(O)cc1)NC(=O)[C@@H]1CCCN1C(=O)[C@@H]1CCCN1C(=O)[C@H](CCCNC(=N)N)NC(=O)[C@@H]1CCCN1C(=O)[C@H](CCCNC(=N)N)NC(=O)[C@H](CCCNC(=N)N)NC(=O)[C@@H](N)CCCNC(=N)N)C(=O)N1CCC[C@H]1C(=O)N1CCC[C@H]1C(=O)NCC(=O)N[C@@H](Cc1ccccc1)C(=O)N1CCC[C@H]1C(=O)N1CCC[C@H]1C(=O)N[C@@H](CCCNC(=N)N)C(=O)N[C@@H](Cc1ccccc1)C(=O)N1CCC[C@H]1C(=O)N1CCC[C@H]1C(=O)N[C@@H](CCCNC(=N)N)C(=O)N[C@@H](Cc1ccccc1)C(=O)N1CCC[C@H]1C(=O)O

InChI

InChI=1S/C229H345N69O41/c1-7-135(6)181(218(337)297-122-50-89-178(297)216(335)283-108-33-72-161(283)190(309)261-132-180(300)262-157(128-137-54-15-9-16-55-137)206(325)293-118-46-84-173(293)212(331)284-109-37-77-166(284)192(311)265-146(65-26-98-254-223(237)238)185(304)276-158(129-138-56-17-10-18-57-138)207(326)294-119-47-85-174(294)213(332)286-111-39-78-167(286)193(312)266-147(66-27-99-255-224(239)240)186(305)277-160(131-140-60-21-12-22-61-140)209(328)298-123-51-90-179(298)219(338)339)279-187(306)148(67-28-100-256-225(241)242)267-194(313)168-79-40-112-287(168)211(330)172-83-45-117-292(172)205(324)156(125-134(4)5)274-184(303)145(64-25-97-253-222(235)236)264-191(310)165-76-38-110-285(165)214(333)175-86-48-120-295(175)208(327)159(130-139-58-19-11-20-59-139)278-189(308)153(126-136-52-13-8-14-53-136)272-198(317)170-81-42-114-289(170)215(334)177-88-49-121-296(177)217(336)176-87-44-116-291(176)203(322)152(71-32-104-260-229(249)250)271-196(315)163-74-35-106-281(163)201(320)150(69-30-102-258-227(245)246)269-197(316)164-75-36-107-282(164)204(323)155(124-133(2)3)275-188(307)154(127-141-91-93-142(299)94-92-141)273-199(318)169-80-41-113-288(169)210(329)171-82-43-115-290(171)202(321)151(70-31-103-259-228(247)248)270-195(314)162-73-34-105-280(162)200(319)149(68-29-101-257-226(243)244)268-183(302)144(63-24-96-252-221(233)234)263-182(301)143(230)62-23-95-251-220(231)232/h8-22,52-61,91-94,133-135,143-179,181,299H,7,23-51,62-90,95-132,230H2,1-6H3,(H,261,309)(H,262,300)(H,263,301)(H,264,310)(H,265,311)(H,266,312)(H,267,313)(H,268,302)(H,269,316)(H,270,314)(H,271,315)(H,272,317)(H,273,318)(H,274,303)(H,275,307)(H,276,304)(H,277,305)(H,278,308)(H,279,306)(H,338,339)(H4,231,232,251)(H4,233,234,252)(H4,235,236,253)(H4,237,238,254)(H4,239,240,255)(H4,241,242,256)(H4,243,244,257)(H4,245,246,258)(H4,247,248,259)(H4,249,250,260)/t135-,143-,144-,145-,146-,147-,148-,149-,150-,151-,152-,153-,154-,155-,156-,157-,158-,159-,160-,161-,162-,163-,164-,165-,166-,167-,168-,169-,170-,171-,172-,173-,174-,175-,176-,177-,178-,179-,181-/m0/s1

Also called

L-arginyl-L-arginyl-L-arginyl-L-prolyl-L-arginyl-L-prolyl-L-prolyl-L-tyrosyl-L-leucyl-L-prolyl-L-arginyl-L-prolyl-L-arginyl-L-prolyl-L-prolyl-L-prolyl-L-phenylalanyl-L-phenylalanyl-L-prolyl-L-prolyl-L-arginyl-L-leucyl-L-prolyl-L-prolyl-L-arginyl-L-isoleucyl-L-prolyl-L-prolylglycyl-L-phenylalanyl-L-prolyl-L-prolyl-L-arginyl-L-phenylalanyl-L-prolyl-L-prolyl-L-arginyl-L-phenylalanyl-L-prolinamide (EXACT_SYNONYM)— chebi
H-Arg-Arg-Arg-Pro-Arg-Pro-Pro-Tyr-Leu-Pro-Arg-Pro-Arg-Pro-Pro-Pro-Phe-Phe-Pro-Pro-Arg-Leu-Pro-Pro-Arg-Ile-Pro-Pro-Gly-Phe-Pro-Pro-Arg-Phe-Pro-Pro-Arg-Phe-Pro-OH (EXACT_SYNONYM)— chebi
H-L-Arg-L-Arg-L-Arg-L-Pro-L-Arg-L-Pro-L-Pro-L-Tyr-L-Leu-L-Pro-L-Arg-L-Pro-L-Arg-L-Pro-L-Pro-L-Pro-L-Phe-L-Phe-L-Pro-L-Pro-L-Arg-L-Leu-L-Pro-L-Pro-L-Arg-L-Ile-L-Pro-L-Pro-Gly-L-Phe-L-Pro-L-Pro-L-Arg-L-Phe-L-Pro-L-Pro-L-Arg-L-Phe-L-Pro-NH2 (EXACT_SYNONYM)— chebi
L-Arg-L-Arg-L-Arg-L-Pro-L-Arg-L-Pro-L-Pro-L-Tyr-L-Leu-L-Pro-L-Arg-L-Pro-L-Arg-L-Pro-L-Pro-L-Pro-L-Phe-L-Phe-L-Pro-L-Pro-L-Arg-L-Leu-L-Pro-L-Pro-L-Arg-L-Ile-L-Pro-L-Pro-Gly-L-Phe-L-Pro-L-Pro-L-Arg-L-Phe-L-Pro-L-Pro-L-Arg-L-Phe-L-Pro (EXACT_SYNONYM)— chebi
PR 39 (EXACT_SYNONYM)— chebi
RRRPRPPYLPRPRPPPFFPPRLPPRIPPGFPPRFPPRFP (EXACT_SYNONYM)— chebi

Cross-references

Identifiers for this same structure in other resources. An accession that lands on two different structures in this corpus is withheld from both rather than shown here, since it names at most one of them.

cas:139637-11-9

Activity roles

Every antimicrobial role a source asserts for this compound — the unreduced evidence behind its antimicrobial_class.

antimicrobial agent CHEBI:33281
antibacterial agent CHEBI:33282
antifungal agent CHEBI:35718

Source concepts

Every upstream concept that resolved to this record. The merge is the product: this is what shows ChEBI and CARD are describing the same structure.

Upstream concepts merged into this record
Source	Native ID	Label	Minted CURIE	Version
CHEBI	`CHEBI:131850`	PR-39	`antibioticmech:chebi-43097ef537`	2026-08-30

Molecular targets

The molecular entity or process this compound acts on. Each target carries evidence — this is a mechanistic claim, not a classification.

bacterial cytoplasmic membrane MEMBRANE ATTACKED_COMPONENT

Mature PR-39 caused ATP leakage and loss of membrane potential in B. globigii and E. coli; a separate Salmonella study observed killing without cell lysis, bounding the membrane-disruption interpretation. Evidence status: PRIMARY_EVIDENCE. Source: PRIMARY_LITERATURE 2014-04 (retrieved 2026-09-02).

PMID:24755622 (Primary mature-PR-39 and derivative membrane-potential/ATP-leakage study (DOI:10.1371/journal.pone.0095939).)
PMID:18519732 (Primary Salmonella PR-39 resistance and non-lytic-killing study (DOI:10.1128/AAC.00205-08).)

SbmA peptide transporter PROTEIN SUSCEPTIBILITY_DETERMINANT

Independent Salmonella mutants with altered SbmA were about fourfold less susceptible and killed more slowly. This establishes a genetic susceptibility determinant, but the study did not directly measure peptide uptake or identify SbmA as the lethal binding target. Evidence status: PRIMARY_EVIDENCE. Source: PRIMARY_LITERATURE 2008-06 (retrieved 2026-09-02).

PMID:18519732 (Primary SbmA mutant selection, susceptibility, killing-rate, and fitness study (DOI:10.1128/AAC.00205-08).)

Mechanism summary

Mode of action: MEMBRANE_DISRUPTION host shared target — CURATOR: PMID:24755622 found that mature PR-39 caused ATP leakage and loss of membrane potential in Bacillus globigii and Escherichia coli. PMID:18519732 showed killing of Salmonella without overt cell lysis and identified SbmA loss-of-function mutations that reduced susceptibility. Together these data support membrane permeabilization/depolarization with SbmA-linked susceptibility, not universal gross lysis or directly measured SbmA-dependent uptake.

Resistance mechanisms

1 source-backed resistance determinants or associations, with ARO grounding where reported. Grouped by reported mechanism type.

OTHER 1

OTHER
Determinant	ARO ID	Organism	Gene families	Evidence
SbmA alterations reduce PR-39 susceptibility Salmonella enterica serovar Typhimurium mutants with SbmA alterations were about fourfold less susceptible and showed slower killing without an obvious measured fitness cost. The study called SbmA a putative transport protein but did not directly measure uptake, so the specific resistance route remains unresolved. Aggregate of LT2-derived mutants, not one experimental allele. The LT2 reference-protein crosswalk is retained separately; no reference strain TaxID, protein accession or genome is assigned to the mutants. The source gene symbol sbmA is retained without variant-coordinate normalization.	—	Salmonella enterica `NCBITaxon:28901` sbmA	sbmA	PMID:18519732 (Primary PR-39 resistance selection, genetic analysis, and fitness study.) https://rest.uniprot.org/taxonomy/28901 (Taxonomic identity only: active species, UniProt release 2026_03; retrieved 2026-10-08 UTC.) https://www.uniprot.org/uniprotkb/Q8ZRF5/entry (Reference-only UniProtKB:Q8ZRF5 (sbmA); UniProtKB unreviewed (TrEMBL), entry version 106, sequence version 1, release 2026_03; retrieved 2026-10-08. Reference organism NCBITaxon:99287, not an experimental subject assignment. Not an exact tested allele, altered protein, strain or genome identifier, and not independent phenotype or mechanism evidence. A component reference does not assign the effect of a combined genotype to that component. UniProt Consortium, CC BY 4.0.)

Record-level evidence

PMID:18519732 (Primary PR-39 Salmonella resistance, SbmA genetics, killing, and fitness study.)
PMID:24755622 (Primary mature-PR-39 membrane-potential, ATP-leakage, spectrum, and cytotoxicity study.)

Curation history

SEEDED_FROM_SOURCES 2026-08-30 · seed_from_sources
Seeded from data/raw/ inventories (CHEBI)
RESEEDED_FROM_SOURCES 2026-08-30 · seed_from_sources
Re-seeded from updated data/raw/ inventories
RESEEDED_FROM_SOURCES 2026-08-30 · seed_from_sources
Re-seeded from updated data/raw/ inventories
REVIEWED 2026-09-03 · codex · LLM-assisted
Verified exact ChEBI peptide identity, structure, antimicrobial roles, and class; added membrane disruption with the non-lysis boundary and SbmA as an evidence-backed susceptibility/resistance determinant while preserving the unresolved uptake-mechanism gap.
GROUNDED_RESISTANCE_CONTEXT 2026-10-08 · codex · LLM-assisted
Grounded the existing aggregate claim to a verified species and clarified experimental versus reference context. No exact mutant protein, strain TaxID, genome, variant normalization or quantitative endpoint added.
GROUNDED_RESISTANCE_REFERENCE_CITATIONS 2026-10-14 · codex · LLM-assisted
Added qualified UniProt evidence citations for reference proteins already verified in the research dossier. Preserved all biological assertions, experimental identity fields, activities and existing evidence. Reference citations are not tested alleles, altered proteins or independent resistance evidence; no strain TaxID, genome, variant or quantitative endpoint added. Whole-record review remains open.

Provenance

Seeded by scripts/seed_from_sources.py from the committed inventories in data/raw/. View the record (YAML).

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