UniProtKB - P11177 (ODPB_HUMAN)
Pyruvate dehydrogenase E1 component subunit beta, mitochondrial
PDHB
Functioni
The pyruvate dehydrogenase complex catalyzes the overall conversion of pyruvate to acetyl-CoA and CO2, and thereby links the glycolytic pathway to the tricarboxylic cycle.
2 PublicationsCatalytic activityi
- (R)-N6-lipoyl-L-lysyl-[dihydrolipoyllysine-residue acetyltransferase] + H+ + pyruvate = (R)-N6-(S8-acetyldihydrolipoyl)-L-lysyl-[dihydrolipoyllysine-residue acetyltransferase] + CO21 PublicationEC:1.2.4.11 Publication
Cofactori
Sites
Feature key | Position(s) | DescriptionActions | Graphical view | Length |
---|---|---|---|---|
Binding sitei | 89 | Thiamine pyrophosphate1 Publication | 1 | |
Sitei | 319 | Important for interaction with DLAT1 Publication | 1 |
GO - Molecular functioni
- pyruvate dehydrogenase (acetyl-transferring) activity Source: GO_Central
GO - Biological processi
- acetyl-CoA biosynthetic process from pyruvate Source: UniProtKB
- glucose metabolic process Source: UniProtKB-KW
- mitochondrial acetyl-CoA biosynthetic process from pyruvate Source: MGI
- tricarboxylic acid cycle Source: ProtInc
Keywordsi
Molecular function | Oxidoreductase |
Biological process | Carbohydrate metabolism, Glucose metabolism, Tricarboxylic acid cycle |
Ligand | Pyruvate, Thiamine pyrophosphate |
Enzyme and pathway databases
PathwayCommonsi | P11177 |
Reactomei | R-HSA-204174, Regulation of pyruvate dehydrogenase (PDH) complex R-HSA-389661, Glyoxylate metabolism and glycine degradation R-HSA-5362517, Signaling by Retinoic Acid R-HSA-70268, Pyruvate metabolism |
SABIO-RKi | P11177 |
SignaLinki | P11177 |
SIGNORi | P11177 |
Names & Taxonomyi
Protein namesi | Recommended name: Pyruvate dehydrogenase E1 component subunit beta, mitochondrial (EC:1.2.4.1)Short name: PDHE1-B |
Gene namesi | Name:PDHB Synonyms:PHE1B |
Organismi | Homo sapiens (Human) |
Taxonomic identifieri | 9606 [NCBI] |
Taxonomic lineagei | Eukaryota › Metazoa › Chordata › Craniata › Vertebrata › Euteleostomi › Mammalia › Eutheria › Euarchontoglires › Primates › Haplorrhini › Catarrhini › Hominidae › Homo |
Proteomesi |
|
Organism-specific databases
HGNCi | HGNC:8808, PDHB |
MIMi | 179060, gene |
neXtProti | NX_P11177 |
VEuPathDBi | HostDB:ENSG00000168291 |
Subcellular locationi
Mitochondrion
Mitochondrion
- mitochondrial matrix Source: Reactome
- mitochondrial pyruvate dehydrogenase complex Source: ComplexPortal
- mitochondrion Source: HPA
Nucleus
- nucleoplasm Source: HPA
- nucleus Source: UniProtKB
Other locations
- pyruvate dehydrogenase complex Source: UniProtKB
Keywords - Cellular componenti
MitochondrionPathology & Biotechi
Involvement in diseasei
Pyruvate dehydrogenase E1-beta deficiency (PDHBD)1 Publication
Feature key | Position(s) | DescriptionActions | Graphical view | Length |
---|---|---|---|---|
Natural variantiVAR_030954 | 132 | Y → C in PDHBD. 1 PublicationCorresponds to variant dbSNP:rs28935769EnsemblClinVar. | 1 | |
Natural variantiVAR_021058 | 344 | P → S in PDHBD. 1 PublicationCorresponds to variant dbSNP:rs28933391EnsemblClinVar. | 1 |
Mutagenesis
Feature key | Position(s) | DescriptionActions | Graphical view | Length |
---|---|---|---|---|
Mutagenesisi | 259 | E → A or Q: Does not affect interaction with DLAT. 1 Publication | 1 | |
Mutagenesisi | 262 | E → A or Q: Does not affect interaction with DLAT. 1 Publication | 1 | |
Mutagenesisi | 264 | E → A or Q: Does not affect interaction with DLAT. 1 Publication | 1 | |
Mutagenesisi | 319 | D → A: Inhibits interaction with DLAT. Does not affect pyruvate decarboxylase activity. Loss of multienzyme pyruvate dehydrogenase complex activity. 1 Publication | 1 | |
Mutagenesisi | 319 | D → N: Reduces interaction with DLAT. Reduces multienzyme pyruvate dehydrogenase complex activity. Does not affect pyruvate decarboxylase activity. 1 Publication | 1 | |
Mutagenesisi | 359 | I → A: Reduces pyruvate decarboxylase and multienzyme pyruvate dehydrogenase complex activity. Does not affect interaction with DLAT. 1 Publication | 1 | |
Mutagenesisi | 359 | Missing : Reduces pyruvate decarboxylase and multienzyme pyruvate dehydrogenase complex activity. Does not affect interaction with DLAT. 1 Publication | 1 |
Keywords - Diseasei
Disease variantOrganism-specific databases
DisGeNETi | 5162 |
GeneReviewsi | PDHB |
MalaCardsi | PDHB |
MIMi | 614111, phenotype |
OpenTargetsi | ENSG00000168291 |
Orphaneti | 255138, Pyruvate dehydrogenase E1-beta deficiency |
PharmGKBi | PA33152 |
Miscellaneous databases
Pharosi | P11177, Tbio |
Chemistry databases
ChEMBLi | CHEMBL4882 |
DrugBanki | DB00157, NADH DB00119, Pyruvic acid |
Genetic variation databases
BioMutai | PDHB |
DMDMi | 134044259 |
PTM / Processingi
Molecule processing
Feature key | Position(s) | DescriptionActions | Graphical view | Length |
---|---|---|---|---|
Transit peptidei | 1 – 30 | Mitochondrion2 PublicationsAdd BLAST | 30 | |
ChainiPRO_0000020457 | 31 – 359 | Pyruvate dehydrogenase E1 component subunit beta, mitochondrialAdd BLAST | 329 |
Amino acid modifications
Feature key | Position(s) | DescriptionActions | Graphical view | Length |
---|---|---|---|---|
Modified residuei | 67 | PhosphotyrosineBy similarity | 1 | |
Modified residuei | 354 | N6-acetyllysineBy similarity | 1 |
Keywords - PTMi
Acetylation, PhosphoproteinProteomic databases
EPDi | P11177 |
jPOSTi | P11177 |
MassIVEi | P11177 |
MaxQBi | P11177 |
PaxDbi | P11177 |
PeptideAtlasi | P11177 |
PRIDEi | P11177 |
ProteomicsDBi | 52715 [P11177-1] 52716 [P11177-2] 52717 [P11177-3] |
TopDownProteomicsi | P11177-1 [P11177-1] |
2D gel databases
REPRODUCTION-2DPAGEi | IPI00549885 |
SWISS-2DPAGEi | P11177 |
UCD-2DPAGEi | P11177 |
PTM databases
GlyGeni | P11177, 2 sites, 1 O-linked glycan (2 sites) |
iPTMneti | P11177 |
MetOSitei | P11177 |
PhosphoSitePlusi | P11177 |
SwissPalmi | P11177 |
Expressioni
Gene expression databases
Bgeei | ENSG00000168291, Expressed in myocardium and 248 other tissues |
ExpressionAtlasi | P11177, baseline and differential |
Genevisiblei | P11177, HS |
Organism-specific databases
HPAi | ENSG00000168291, Tissue enhanced (skeletal muscle, tongue) |
Interactioni
Subunit structurei
Heterotetramer of two PDHA1 and two PDHB subunits (PubMed:12651851, PubMed:17474719, PubMed:19081061). The heterotetramer interacts with DLAT, and is part of the multimeric pyruvate dehydrogenase complex that contains multiple copies of pyruvate dehydrogenase (E1), dihydrolipoamide acetyltransferase (DLAT, E2) and lipoamide dehydrogenase (DLD, E3) (PubMed:14638692). These subunits are bound to an inner core composed of about 48 DLAT and 12 PDHX molecules (PubMed:14638692).
Interacts with DLAT (PubMed:20160912).
5 PublicationsBinary interactionsi
P11177
With | #Exp. | IntAct |
---|---|---|
DLAT [P10515] | 7 | EBI-1035872,EBI-2959723 |
PDHA1 [P08559] | 4 | EBI-1035872,EBI-715747 |
Isoform 1 [P11177-1]
With | #Exp. | IntAct |
---|---|---|
PDHA1 - isoform 1 [P08559-1] | 4 | EBI-25766519,EBI-25766512 |
Protein-protein interaction databases
BioGRIDi | 111188, 257 interactors |
ComplexPortali | CPX-376, Pyruvate dehydrogenase E1 heterotetramer CPX-6233, Mitochondrial pyruvate dehydrogenase complex, somatic variant CPX-6242, Mitochondrial pyruvate dehydrogenase complex, testis-specific variant |
DIPi | DIP-37651N |
IntActi | P11177, 59 interactors |
MINTi | P11177 |
STRINGi | 9606.ENSP00000307241 |
Miscellaneous databases
RNActi | P11177, protein |
Structurei
Secondary structure
3D structure databases
AlphaFoldDBi | P11177 |
SMRi | P11177 |
ModBasei | Search... |
PDBe-KBi | Search... |
Miscellaneous databases
EvolutionaryTracei | P11177 |
Family & Domainsi
Keywords - Domaini
Transit peptidePhylogenomic databases
eggNOGi | KOG0524, Eukaryota |
GeneTreei | ENSGT00940000155146 |
HOGENOMi | CLU_012907_1_1_1 |
InParanoidi | P11177 |
OMAi | SRMRHHC |
OrthoDBi | 875272at2759 |
PhylomeDBi | P11177 |
TreeFami | TF105674 |
Family and domain databases
Gene3Di | 3.40.50.920, 1 hit |
InterProi | View protein in InterPro IPR027110, PDHB IPR029061, THDP-binding IPR009014, Transketo_C/PFOR_II IPR005475, Transketolase-like_Pyr-bd IPR033248, Transketolase_C |
PANTHERi | PTHR11624, PTHR11624, 1 hit |
Pfami | View protein in Pfam PF02779, Transket_pyr, 1 hit PF02780, Transketolase_C, 1 hit |
SMARTi | View protein in SMART SM00861, Transket_pyr, 1 hit |
SUPFAMi | SSF52518, SSF52518, 1 hit SSF52922, SSF52922, 1 hit |
s (3+)i Sequence
Sequence statusi: Complete.
: The displayed sequence is further processed into a mature form. Sequence processingi
This entry describes 3 produced by isoformsialternative splicing. AlignAdd to basketThis entry has 3 described isoforms and 2 potential isoforms that are computationally mapped.Show allAlign All
This isoform has been chosen as the sequence. All positional information in this entry refers to it. This is also the sequence that appears in the downloadable versions of the entry. canonicali
10 20 30 40 50
MAAVSGLVRR PLREVSGLLK RRFHWTAPAA LQVTVRDAIN QGMDEELERD
60 70 80 90 100
EKVFLLGEEV AQYDGAYKVS RGLWKKYGDK RIIDTPISEM GFAGIAVGAA
110 120 130 140 150
MAGLRPICEF MTFNFSMQAI DQVINSAAKT YYMSGGLQPV PIVFRGPNGA
160 170 180 190 200
SAGVAAQHSQ CFAAWYGHCP GLKVVSPWNS EDAKGLIKSA IRDNNPVVVL
210 220 230 240 250
ENELMYGVPF EFPPEAQSKD FLIPIGKAKI ERQGTHITVV SHSRPVGHCL
260 270 280 290 300
EAAAVLSKEG VECEVINMRT IRPMDMETIE ASVMKTNHLV TVEGGWPQFG
310 320 330 340 350
VGAEICARIM EGPAFNFLDA PAVRVTGADV PMPYAKILED NSIPQVKDII
FAIKKTLNI
Computationally mapped potential isoform sequencesi
There are 2 potential isoforms mapped to this entry.BLASTAlignShow allAdd to basketC9J634 | C9J634_HUMAN | Pyruvate dehydrogenase E1 component... | PDHB | 350 | Annotation score: | ||
F8WF02 | F8WF02_HUMAN | Pyruvate dehydrogenase E1 component... | PDHB | 251 | Annotation score: |
Experimental Info
Feature key | Position(s) | DescriptionActions | Graphical view | Length |
---|---|---|---|---|
Sequence conflicti | 9 – 13 | RRPLR → AETPS (PubMed:3422424).Curated | 5 | |
Sequence conflicti | 43 | M → G AA sequence (PubMed:7895732).Curated | 1 | |
Sequence conflicti | 160 | Q → G (PubMed:3422424).Curated | 1 | |
Sequence conflicti | 213 – 221 | PPEAQSKDF → LRKLSQKIL (PubMed:3422424).Curated | 9 | |
Sequence conflicti | 213 | P → L in AAA88097 (PubMed:2377599).Curated | 1 | |
Sequence conflicti | 213 | P → L in BAA14123 (PubMed:2377599).Curated | 1 | |
Sequence conflicti | 310 – 312 | MEG → NGS (PubMed:3422424).Curated | 3 |
Natural variant
Feature key | Position(s) | DescriptionActions | Graphical view | Length |
---|---|---|---|---|
Natural variantiVAR_004967 | 31 | L → V2 Publications | 1 | |
Natural variantiVAR_030954 | 132 | Y → C in PDHBD. 1 PublicationCorresponds to variant dbSNP:rs28935769EnsemblClinVar. | 1 | |
Natural variantiVAR_021058 | 344 | P → S in PDHBD. 1 PublicationCorresponds to variant dbSNP:rs28933391EnsemblClinVar. | 1 |
Alternative sequence
Feature key | Position(s) | DescriptionActions | Graphical view | Length |
---|---|---|---|---|
Alternative sequenceiVSP_012675 | 16 – 33 | Missing in isoform 2. 1 PublicationAdd BLAST | 18 | |
Alternative sequenceiVSP_043364 | 135 – 152 | Missing in isoform 3. 1 PublicationAdd BLAST | 18 |
Sequence databases
Select the link destinations: EMBLi GenBanki DDBJi Links Updated | M34479 mRNA Translation: AAA36428.1 M19123 mRNA Translation: AAA60052.1 Sequence problems. M54788 mRNA Translation: AAA60053.1 M34055 mRNA Translation: AAA60233.1 M34056 mRNA Translation: AAA60054.1 D90086 Genomic DNA Translation: BAA14123.1 J03576 mRNA Translation: AAA88097.1 AL117618 mRNA Translation: CAB56017.1 CR541911 mRNA Translation: CAG46709.1 AK293153 mRNA Translation: BAG56698.1 AK313022 mRNA Translation: BAG35857.1 AC135507 Genomic DNA No translation available. CH471055 Genomic DNA Translation: EAW65371.1 BC000439 mRNA Translation: AAH00439.1 BC001924 mRNA Translation: AAH01924.1 X57778 mRNA Translation: CAA40924.1 |
CCDSi | CCDS2890.1 [P11177-1] CCDS54602.1 [P11177-3] CCDS82795.1 [P11177-2] |
PIRi | JU0145, DEHUPB |
RefSeqi | NP_000916.2, NM_000925.3 [P11177-1] NP_001166939.1, NM_001173468.1 [P11177-3] NP_001302465.1, NM_001315536.1 [P11177-2] |
Genome annotation databases
Ensembli | ENST00000302746.11; ENSP00000307241.6; ENSG00000168291.13 ENST00000383714.8; ENSP00000373220.4; ENSG00000168291.13 [P11177-2] ENST00000485460.5; ENSP00000417267.1; ENSG00000168291.13 [P11177-3] |
GeneIDi | 5162 |
KEGGi | hsa:5162 |
MANE-Selecti | ENST00000302746.11; ENSP00000307241.6; NM_000925.4; NP_000916.2 |
UCSCi | uc003dkf.4, human [P11177-1] |
Keywords - Coding sequence diversityi
Alternative splicingSimilar proteinsi
Cross-referencesi
Sequence databases
Select the link destinations: EMBLi GenBanki DDBJi Links Updated | M34479 mRNA Translation: AAA36428.1 M19123 mRNA Translation: AAA60052.1 Sequence problems. M54788 mRNA Translation: AAA60053.1 M34055 mRNA Translation: AAA60233.1 M34056 mRNA Translation: AAA60054.1 D90086 Genomic DNA Translation: BAA14123.1 J03576 mRNA Translation: AAA88097.1 AL117618 mRNA Translation: CAB56017.1 CR541911 mRNA Translation: CAG46709.1 AK293153 mRNA Translation: BAG56698.1 AK313022 mRNA Translation: BAG35857.1 AC135507 Genomic DNA No translation available. CH471055 Genomic DNA Translation: EAW65371.1 BC000439 mRNA Translation: AAH00439.1 BC001924 mRNA Translation: AAH01924.1 X57778 mRNA Translation: CAA40924.1 |
CCDSi | CCDS2890.1 [P11177-1] CCDS54602.1 [P11177-3] CCDS82795.1 [P11177-2] |
PIRi | JU0145, DEHUPB |
RefSeqi | NP_000916.2, NM_000925.3 [P11177-1] NP_001166939.1, NM_001173468.1 [P11177-3] NP_001302465.1, NM_001315536.1 [P11177-2] |
3D structure databases
Select the link destinations: PDBei RCSB PDBi PDBji Links Updated | PDB entry | Method | Resolution (Å) | Chain | Positions | PDBsum |
1NI4 | X-ray | 1.95 | B/D | 31-359 | [»] | |
2OZL | X-ray | 1.90 | B/D | 32-359 | [»] | |
3EXE | X-ray | 1.98 | B/D/F/H | 31-359 | [»] | |
3EXF | X-ray | 3.00 | B/D/F/H | 31-359 | [»] | |
3EXG | X-ray | 3.01 | 2/4/6/B/D/F/H/J/L/N/P/R/T/V/X/Z | 31-359 | [»] | |
3EXH | X-ray | 2.44 | B/D/F/H | 31-359 | [»] | |
3EXI | X-ray | 2.20 | B | 31-359 | [»] | |
6CER | X-ray | 2.69 | B/D/F/H | 31-359 | [»] | |
6CFO | X-ray | 2.70 | B/D | 31-359 | [»] | |
AlphaFoldDBi | P11177 | |||||
SMRi | P11177 | |||||
ModBasei | Search... | |||||
PDBe-KBi | Search... |
Protein-protein interaction databases
BioGRIDi | 111188, 257 interactors |
ComplexPortali | CPX-376, Pyruvate dehydrogenase E1 heterotetramer CPX-6233, Mitochondrial pyruvate dehydrogenase complex, somatic variant CPX-6242, Mitochondrial pyruvate dehydrogenase complex, testis-specific variant |
DIPi | DIP-37651N |
IntActi | P11177, 59 interactors |
MINTi | P11177 |
STRINGi | 9606.ENSP00000307241 |
Chemistry databases
ChEMBLi | CHEMBL4882 |
DrugBanki | DB00157, NADH DB00119, Pyruvic acid |
PTM databases
GlyGeni | P11177, 2 sites, 1 O-linked glycan (2 sites) |
iPTMneti | P11177 |
MetOSitei | P11177 |
PhosphoSitePlusi | P11177 |
SwissPalmi | P11177 |
Genetic variation databases
BioMutai | PDHB |
DMDMi | 134044259 |
2D gel databases
REPRODUCTION-2DPAGEi | IPI00549885 |
SWISS-2DPAGEi | P11177 |
UCD-2DPAGEi | P11177 |
Proteomic databases
EPDi | P11177 |
jPOSTi | P11177 |
MassIVEi | P11177 |
MaxQBi | P11177 |
PaxDbi | P11177 |
PeptideAtlasi | P11177 |
PRIDEi | P11177 |
ProteomicsDBi | 52715 [P11177-1] 52716 [P11177-2] 52717 [P11177-3] |
TopDownProteomicsi | P11177-1 [P11177-1] |
Protocols and materials databases
Antibodypediai | 31652, 241 antibodies from 34 providers |
DNASUi | 5162 |
Genome annotation databases
Ensembli | ENST00000302746.11; ENSP00000307241.6; ENSG00000168291.13 ENST00000383714.8; ENSP00000373220.4; ENSG00000168291.13 [P11177-2] ENST00000485460.5; ENSP00000417267.1; ENSG00000168291.13 [P11177-3] |
GeneIDi | 5162 |
KEGGi | hsa:5162 |
MANE-Selecti | ENST00000302746.11; ENSP00000307241.6; NM_000925.4; NP_000916.2 |
UCSCi | uc003dkf.4, human [P11177-1] |
Organism-specific databases
CTDi | 5162 |
DisGeNETi | 5162 |
GeneCardsi | PDHB |
GeneReviewsi | PDHB |
HGNCi | HGNC:8808, PDHB |
HPAi | ENSG00000168291, Tissue enhanced (skeletal muscle, tongue) |
MalaCardsi | PDHB |
MIMi | 179060, gene 614111, phenotype |
neXtProti | NX_P11177 |
OpenTargetsi | ENSG00000168291 |
Orphaneti | 255138, Pyruvate dehydrogenase E1-beta deficiency |
PharmGKBi | PA33152 |
VEuPathDBi | HostDB:ENSG00000168291 |
GenAtlasi | Search... |
Phylogenomic databases
eggNOGi | KOG0524, Eukaryota |
GeneTreei | ENSGT00940000155146 |
HOGENOMi | CLU_012907_1_1_1 |
InParanoidi | P11177 |
OMAi | SRMRHHC |
OrthoDBi | 875272at2759 |
PhylomeDBi | P11177 |
TreeFami | TF105674 |
Enzyme and pathway databases
PathwayCommonsi | P11177 |
Reactomei | R-HSA-204174, Regulation of pyruvate dehydrogenase (PDH) complex R-HSA-389661, Glyoxylate metabolism and glycine degradation R-HSA-5362517, Signaling by Retinoic Acid R-HSA-70268, Pyruvate metabolism |
SABIO-RKi | P11177 |
SignaLinki | P11177 |
SIGNORi | P11177 |
Miscellaneous databases
BioGRID-ORCSi | 5162, 40 hits in 1084 CRISPR screens |
ChiTaRSi | PDHB, human |
EvolutionaryTracei | P11177 |
GeneWikii | Pyruvate_dehydrogenase_(lipoamide)_beta |
GenomeRNAii | 5162 |
Pharosi | P11177, Tbio |
PROi | PR:P11177 |
RNActi | P11177, protein |
SOURCEi | Search... |
Gene expression databases
Bgeei | ENSG00000168291, Expressed in myocardium and 248 other tissues |
ExpressionAtlasi | P11177, baseline and differential |
Genevisiblei | P11177, HS |
Family and domain databases
Gene3Di | 3.40.50.920, 1 hit |
InterProi | View protein in InterPro IPR027110, PDHB IPR029061, THDP-binding IPR009014, Transketo_C/PFOR_II IPR005475, Transketolase-like_Pyr-bd IPR033248, Transketolase_C |
PANTHERi | PTHR11624, PTHR11624, 1 hit |
Pfami | View protein in Pfam PF02779, Transket_pyr, 1 hit PF02780, Transketolase_C, 1 hit |
SMARTi | View protein in SMART SM00861, Transket_pyr, 1 hit |
SUPFAMi | SSF52518, SSF52518, 1 hit SSF52922, SSF52922, 1 hit |
MobiDBi | Search... |
Entry informationi
Entry namei | ODPB_HUMAN | |
Accessioni | P11177Primary (citable) accession number: P11177 Secondary accession number(s): B2R7L0 Q9UFK3 | |
Entry historyi | Integrated into UniProtKB/Swiss-Prot: | July 1, 1989 |
Last sequence update: | March 6, 2007 | |
Last modified: | May 25, 2022 | |
This is version 238 of the entry and version 3 of the sequence. See complete history. | ||
Entry statusi | Reviewed (UniProtKB/Swiss-Prot) | |
Annotation program | Chordata Protein Annotation Program | |
Disclaimer | Any medical or genetic information present in this entry is provided for research, educational and informational purposes only. It is not in any way intended to be used as a substitute for professional medical advice, diagnosis, treatment or care. |
Miscellaneousi
Keywords - Technical termi
3D-structure, Direct protein sequencing, Reference proteomeDocuments
- Human chromosome 3
Human chromosome 3: entries, gene names and cross-references to MIM - Human entries with genetic variants
List of human entries with genetic variants - Human variants curated from literature reports
Index of human variants curated from literature reports - MIM cross-references
Online Mendelian Inheritance in Man (MIM) cross-references in UniProtKB/Swiss-Prot - PDB cross-references
Index of Protein Data Bank (PDB) cross-references