efi-genome neighborhood tool: a web tool for large-scale analysis of genome context
DESCRIPTION
EFI-Genome Neighborhood Tool: a web tool for large-scale analysis of genome context Enzyme Function Initiative (EFI) Gordon Research Conference on Enzymes, Coenzymes, and Metabolic Pathways July 15, 2014. What is a Genome Neighborhood Network?. High sequence homology. Enzyme function. - PowerPoint PPT PresentationTRANSCRIPT
EFI-Genome Neighborhood Tool: a web tool for large-scale analysis of genome
context
Enzyme Function Initiative (EFI)Gordon Research Conference on
Enzymes, Coenzymes, and Metabolic PathwaysJuly 15, 2014
What is a Genome Neighborhood Network?
High sequence homology Enzyme function
Low/Med. Sequence homology + Genome Context Enzyme function
What is a Genome Neighborhood Network?
Genes << Operon << Regulon
gene products forming a biological pathway
R A B C
Genome neighborhood information facilitates enzyme function discovery via contextual evidence
What is a Genome Neighborhood Network?
The GNN organizes genome neighborhood information for thousands of query genes in a high throughput and rapid fashion.
The resulting network allows a user to quickly identify the protein families that are encoded by the genes within close proximity to the SSN dataset.
GNN Generation
The entire process is fast and computationally inexpensive
SSN Cluster Inventory
Neighbor Annotation Gathering Network Generation
• SSN network file parsing
• Singletons excluded
• Clusters assigned number and unique color
• European Nucleotide Archive (ENA) is queried with each SSN sequence
• Protein-encoding genes are compared to Pfam
• Additional annotation information is gathered
• Network xgmml file written
• Query sequences and neighbor sequences = nodes
• Genome proximity = edge
Query families
GNNs: query families
Genome neighbors
GNNs: bacterial proteins in gene clusters
Query families
Genome neighbors
GNNs: collect neighbors
Query families
Genome neighbors network for neighbors
GNNs: cluster neighbors
Query families
Genome neighbors network for neighbors
shared contextsame pathwaysame function
unique contextunique pathwayunique function
GNNs: deduce function
Query families
Example: proline racemase superfamily< 10-120
> 60% ID
Zhao et al. 2014 eLife: http://dx.doi.org/10.7554/eLife.03275
GNN: “BLAST” network
GNN: Pfam network
Full GNN Pfam GNN
GNN: pathway “parts”
ALDH DAO
DHDPS
OCD
LDH/MDH
From GNN: complete pathways
DAO
DHDPS
ALDH
OCD LDH/MDH
GNN Format
The GNN visually organizes genome neighborhood information into multiple hub-and-spoke clusters.
Hub Nodes
Hub node = Pfam family in neighborhood
Node Attribute, Neighbor_Accessions = list of all Pfam members found in genome context of SSN, with the following additional information:• EC number • PDB code • PDB-hit • Swiss-Prot status (reviewed/unreviewed)
Additional Node Attributes:
• Num_neighbors = the number of neighbor sequences belonging to this Pfam family
• pfam = Pfam number, e.g., PF13365• Pfam description = a short description of the family, e.g., Trypsin-like peptidase
domain
PDB-Hit
PDB-hit - a sequence shares significant (e-value < e-15) homology with a protein with an X-ray crystal structure in RCSB Protein DataBase.
The format of this information is “PDB code:e-value”
Related structure homology model for docking
For users that are new to homology modeling, see resources by Sali lab at the University of California at San Francisco.
PDB284k
UniProt48M
PDB-Hit Database
22M
BLASTp
Spoke Nodes
Spoke nodes = single cluster from SSN with ≥1 neighbor in hub
The Node Attributes:• Cluster Number = # assigned to SSN-cluster • Query_Accessions = a list of UniProt accessions for
query sequences• Distance = a list of distance between query and neighbor.
This is formatted “UniprotID-query:UniprotID-neighbor: (-)N”, where query = 0, next gene = 1, etc., and a negative N value indicates an upstream position.
• SSN Cluster Size = the size of SSN-cluster• Num_neighbors = # of neighbor sequences retrieved by
spoke node• Num_queries = # of query sequences in spoke node• Num_ratio = % co-occurrence as a ratio• ClusterFraction = % co-occurrence as fraction, 0-3
Spoke Nodes
Spoke node size is dependent on the % co-occurrence of that Pfam in the neighborhood of that SSN cluster.
% co-occurrence = # neighbors retrieved / SSN cluster size * 100
% Co-Occurrence Indicative Situation< 100% The neighbor gene is not well-conserved and potentially
unimportant to the physiological pathway of the query gene.
< 100% This particular SSN-cluster is not isofunctional, containing multiple neighborhood contexts.
≈ 100% The neighbor gene is a well-conserved member of the genome neighborhood.
> 100% Two or more instances of neighbors from this particular Pfam family exist in the genome neighborhood.
Pfam and the GNN
www.pfam.xfam.org
More universal
Unique
Highly represented in SSN cluster
Lowly represented in SSN cluster
Pfam and the GNN
www.pfam.xfam.org
Identify the general classes of enzymes present in the genome context of an SSN cluster.
Eg., the presence of a kinase Pfam family and isomerase Pfam family, may indicate that the proteins of this particular SSN-cluster may carry out an aldolase-type reaction for a catabolic pathway.
Kinase Pfam
Isomerase Pfam
Neighborhood Size
EFI-GNT default neighborhood size = +10 and -10 genes
Users may lower this to +/- 3 to 9 genes
R A B C
Zheng et al. 2002, Genome Research 12, 1221
GNN Signal-to-Noise: Added Noise
The utility of the GNN is limited primarily by its signal-to-noise
Signal = proximal and functionally related genesNoise = proximal and irrelevant genes
Source of Noise RemedyDistant genes Decrease neighborhood size
Uncommonly co-occurring genes
Increase co-occurrence threshold
SSN over-fractionation Return SSN to less stringent e-value
GNN Signal-to-Noise: Lost Signal
Why did my query sequence return less than 20 neighbors?
• Query sequence does not match to the ENA sub-databases • Non-coding RNA• Query sequence is located near the beginning or end of the ENA file• The neighbor entry does not have an associated EMBL accession number • The neighbor entry has not been incorporated into a current Pfam family.
R A B C X X
EFI-GNT Web tool
www.enzymefunction.org
EFI-GNT Input
1. Upload xgmml network, full or rep-node
2. Pick neighborhood size: 3-10 +/- genes
4. Enter email address
www.efi.igb.illinois.edu/efi-gnt
3. Enter co-occurrence cutoff(1-100)
5. Hit “go”
Upload status bar
EFI-GNT Output
The EFI-GNT output is a pair of .xgmml files:
• genome neighborhood network (GNN)
• Colored version of the original SSN
EFI-GNT Output
A download link will be sent to the e-mail address provided.
Data stored on server for 7 days.
EFI-GNT Output
NOTE – depending on your browser, the files may download with an additional file extension, such as: .xgmml.txt or .xgmml.xml
You must delete the .txt or .xml extension in order to open these files in Cytoscape!
Cytoscape opens .xgmml
Network Visualization
GNN files must be viewed in Cytoscape 3.0 (or more recent)
Best layouts: Organic or Prefuse Force Directed
Opening both the GNN and colored SSN in a single instance of Cytoscape allows fast comparison between the two networks (see above).
www.cytoscape.org
Version 3.1.0
Network Visualization
NOTE – in Cytoscape the automatic rendering and coloring of the colorized SSN is size dependent. Cytoscape settings include a “Threshold View” that needs to be adjusted in the following manner in order to automatically view your colored SSN:
• In any version 3.X, go to Edit -> Preferences -> Properties• With “cytoscape 3” selected in the pull-down menu at the
top, scroll to the bottom of the Property list and select “viewThreshold”
• Click “Modify” and insert 5 zeros to the end of the displayed number
• Click “OK”Restart Cytoscape (this should only need to be done once per version of Cytoscape installed on your machine)
Generally, the full +/-10 neighbor GNN presents an overwhelming amount of information.
Filter GNN networks by SNN Cluster Number, in order to assign enzyme function to subgroups of homologous sequences.
Network Manipulation
Only hubs connected to the designated SSN cluster (eg., the cyan cluster 5).
Analyze the genome neighborhood Pfams specific to this SSN-cluster.
Network Manipulation
Network Manipulation
Spoke length is arbitrary.
click+drag+drop overlapping spoke nodes until all are visible
Tutorial Pages
Tutorial pages containing content similar to this presentation
Test Case:Predicted Novelties of the Sialic Acid Degradation
Pathway
Protein SSN
Bacterial extracellular solute-binding protein family 1 (SBP_bac_1, PF01547)
100% rep node netBLAST E-value 10-80
40% identical
21833 sequences11073 nodes
Cluster 16415 membersEFI ID 510644ThermoFluor hit on N-acetyl-neuraminate
J. Bouvier, UIUC
Genome Neighborhood Network for Cluster 164
PermeaseABC transporter
KinaseEpimerase
DUF
DHDPS
Regulator
J. Bouvier, UIUC
EFI ID 510644 gene neighborhood
+6 +4 +2 -2 -4
Pfam Family ID Pfam Description Predicted Role % Occurrence+6 Unassigned None none unavailable
+5 PF01380 PF01418 SIS HTH_6 transcription regulator 93
+4 PF05448 Acetyl xylan esterase deacetylase 7
+3 PF00480 ROK kinase 93
+2 PF00701 DHDPS lyase 93
+1 PF04074 DUF386 isomerase/deaminase 67
PF01547 SBP_bac_1 solute-binding 120
-1 PF00528 BPD_transp_1 permease 120
-2 PF00528 BDP_transp_1 permease 120
-3 PF04131 NanE epimerase 107
-4 PF00468 Ribosomal_L34 ribosome subunit 67
+3 +1 query -1 -3+5
Streptococcus uberis Diernhofer (strain 0140J, ATCC BAA-854)
J. Bouvier, UIUC
N-acetylneuraminate degradation pathway
O O-O
OHOH
HOH
HNOH
OH
O
O
NH
O
OH
HOOH
HO
-O
O
O
O
NH
O
OH
HOOH
OPO-
-OO
N-acetyl-D-mannosamine6-phosphate
N-acetyl-D-mannosaminepyruvateN-acetyl
neuraminate
ATPADPH+
O
NH
O
OH
HOOH
OPO-
-OO
O
NH3+
OH
HOOH
OPO-
-OO
O
OH
OH
HO
OPO
-OO-
OH
glycolysisH2O NH4+H2O
N-acetyl-D-glucosamine6-phosphate
-O
O
acetate D-glucosamine6-phosphate
β-D-fructofuranose6-phopshate
PF00701 PF00480 PF04131
PF01979 PF01182
Enzyme Pfam family ID
J. Bouvier, UIUCFound in GNN Found alternative Pfam Orphan EC
Three sources of unknown enzymes
1. Orphan enzyme activity (EC number with no enzyme) - in vivo evidence suggests an enzyme from PF04131 converts N-acetyl-D-mannosamine 6-phosphate to N-acetyl-D-glucosamine 6-phosphate in the third step of the pathway, but no biochemical work has been done on this putative epimerase.
2. Non orthologous gene replacement - The deacetylase from PF01979 known to convert N-acetyl-D-glucosamine 6-phosphate to D-glucosamine 6-phosphate in the four step of this pathway is located elsewhere in the genome (locus tag Sub1443). However Sub1651 which is located four genes downstream is a member of PF05448, and other members of PF05448 have known deacetylase activity. Is this a non orthologous gene replacement, and does it’s low occurrence (7%) in the neighborhoods of the queries suggest it to be a relic?
3. Domain of unknown function - The deaminase/isomerase from PF01182 known to convert α-D-glucosamine 6-phosphate to β-D-fructofuranose 6-phosphate in the fifth step of the pathway is located elsewhere in the genome (locus tag Sub1239). However Sub1654 which is located one gene downstream has been suggested to be a sugar isomerase. Sub1654 is a member of PF04074 (DUF386). Sub1654 is a good candidate for docking.
J. Bouvier, UIUC
Hands-on Portion of Workshop
Feel free now to download Cytoscape 3.1, run EFI-EST, and run EFI-GNT for your protein (family) of interest.
Please see posters by Katie Whalen (#55) and Daniel Wichelecki (#56) for further examples of EFI-EST/EFI-GNT use.
Tutorials for using Cytoscape: http://enzymefunction.org/resources/tutorials/efi-and-cytoscape3
Feel free to contact us throughout the conference with questions/comments.
Acknowledgements
GNN Development Suwen Zhao (UCSF) Alan Barber (Pythoscape, UCSF) Shoshana Brown (Pythoscape, UCSF) Eyal Akiva (Pythoscape, UCSF) Jason Bouvier (UIUC)
Website Build Daniel Davidson (UIUC) David Slater (UIUC)
Documentation Katie Whalen (UIUC)
Principal Investigators Matthew Jacobson (UCSF) Patricia Babbitt (Pythoscape, UCSF) John Gerlt (UIUC)