N. S. Anderson, T. C. Dolan, and D. A. Rees, Evidence for a common structural pattern in the polysaccharide sulphates of the Rhodophyceae, Nature, vol.205, pp.1060-1062, 1965.

M. Martin, D. Portetelle, G. Michel, and M. Vandenbol, Microorganisms living on macroalgae: diversity, interactions, and biotechnological applications, Appl. Microbiol. Biotechnol, vol.98, pp.2917-2935, 2014.
URL : https://hal.archives-ouvertes.fr/hal-00999506

G. Michel, The kappa-carrageenase of P. carrageenovora features a tunnelshaped active site: a novel insight in the evolution of Clan-B glycoside hydrolases, Structure, vol.9, pp.513-525, 2001.

G. Michel, The iota-carrageenase of Alteromonas fortis. A beta-helix foldcontaining enzyme for the degradation of a highly polyanionic polysaccharide, J. Biol. Chem, vol.276, pp.40202-40209, 2001.

M. Guibet, Degradation of lambda-carrageenan by Pseudoalteromonas carrageenovora lambda-carrageenase: a new family of glycoside hydrolases unrelated to kappa-and iota-carrageenases, Biochem. J, vol.404, pp.105-114, 2007.
URL : https://hal.archives-ouvertes.fr/hal-00478659

A. Prechoux, S. Genicot, H. Rogniaux, and W. Helbert, Controlling carrageenan structure using a novel formylglycine-dependent sulfatase, an endo-4S-iotacarrageenan sulfatase, Mar. Biotechnol, vol.15, pp.265-274, 2013.

A. Prechoux, S. Genicot, H. Rogniaux, and W. Helbert, Enzyme-assisted preparation of furcellaran-like kappa-/beta-carrageenan, Mar. Biotechnol, vol.18, pp.133-143, 2016.

F. Thomas, J. H. Hehemann, E. Rebuffet, M. Czjzek, and G. Michel, Environmental and gut bacteroidetes: the food connection, Front. Microbiol, vol.2, p.93, 2011.
URL : https://hal.archives-ouvertes.fr/hal-00925466

H. Teeling, Substrate-controlled succession of marine bacterioplankton populations induced by a phytoplankton bloom, Science, vol.336, pp.608-611, 2012.

T. Barbeyron, Habitat and taxon as driving forces of carbohydrate catabolism in marine heterotrophic bacteria: example of the model algaeassociated bacterium Zobellia galactanivorans DsijT, Environ. Microbiol, vol.18, pp.4610-4627, 2016.

K. L. Anderson and A. A. Salyers, Genetic evidence that outer membrane binding of starch is required for starch utilization by Bacteroides thetaiotaomicron, J. Bacteriol, vol.171, pp.3199-3204, 1989.

K. L. Anderson and A. A. Salyers, Biochemical evidence that starch breakdown by Bacteroides thetaiotaomicron involves outer membrane starch-binding sites and periplasmic starch-degrading enzymes, J. Bacteriol, vol.171, pp.3192-3198, 1989.

M. K. Bjursell, E. C. Martens, and J. I. Gordon, Functional genomic and metabolic studies of the adaptations of a prominent adult human gut symbiont, Bacteroides thetaiotaomicron, to the suckling period, J. Biol. Chem, vol.281, pp.36269-36279, 2006.

N. Terrapon, V. Lombard, H. J. Gilbert, and B. Henrissat, Automatic prediction of polysaccharide utilization loci in Bacteroidetes species, Bioinformatics, vol.31, pp.647-655, 2015.
URL : https://hal.archives-ouvertes.fr/hal-01438994

E. D. Sonnenburg, Specificity of polysaccharide use in intestinal bacteroides species determines diet-induced microbiota alterations, Cell, vol.141, pp.1241-1252, 2010.

J. Larsbrink, A discrete genetic locus confers xyloglucan metabolism in select human gut Bacteroidetes, Nature, vol.506, pp.498-502, 2014.

F. Cuskin, Human gut Bacteroidetes can utilize yeast mannan through a selfish mechanism, Nature, vol.517, pp.165-169, 2015.

D. Ndeh, Complex pectin metabolism by gut bacteria reveals novel catalytic functions, Nature, vol.544, pp.65-70, 2017.
URL : https://hal.archives-ouvertes.fr/hal-01595600

F. Thomas, Characterization of the first alginolytic operons in a marine bacterium: from their emergence in marine Flavobacteriia to their independent transfers to marine Proteobacteria and human gut Bacteroides, Environ. Microbiol, vol.14, pp.2379-2394, 2012.

J. H. Hehemann, A. G. Kelly, N. A. Pudlo, E. C. Martens, and A. B. Boraston, Bacteria of the human gut microbiome catabolize red seaweed glycans with carbohydrate-active enzyme updates from extrinsic microbes, Proc. Natl Acad. Sci. USA, vol.109, pp.19786-19791, 2012.

V. Lombard, H. Golaconda-ramulu, E. Drula, P. M. Coutinho, and B. Henrissat, The carbohydrate-active enzymes database (CAZy) in 2013, Nucleic Acids Res, vol.42, pp.490-495, 2014.

T. Barbeyron, A. Gerard, P. Potin, B. Henrissat, and B. Kloareg, The kappacarrageenase of the marine bacterium Cytophaga drobachiensis. Structural and phylogenetic relationships within family-16 glycoside hydrolases, Mol. Biol. Evol, vol.15, pp.528-537, 1998.

T. Barbeyron, G. Michel, P. Potin, B. Henrissat, and B. Kloareg, iotaCarrageenases constitute a novel family of glycoside hydrolases, unrelated to that of kappa-carrageenases, J. Biol. Chem, vol.275, pp.35499-35505, 2000.

E. Rebuffet, Identification of catalytic residues and mechanistic analysis of family GH82 iota-carrageenases, Biochemistry, vol.49, pp.7590-7599, 2010.

J. Craigie and . Walls, Biology of the red algae, 1990.

T. Barbeyron, Matching the diversity of sulfated biomolecules: creation of a classification database for sulfatases reflecting their substrate specificity, PLoS ONE, vol.11, p.164846, 2016.
URL : https://hal.archives-ouvertes.fr/hal-01409013

K. Fujita, Y. Takashi, E. Obuchi, K. Kitahara, and T. Suganuma, Characterization of a novel beta-L-arabinofuranosidase in Bifidobacterium longum: functional elucidation of a DUF1680 protein family member, J. Biol. Chem, vol.289, pp.5240-5249, 2014.

M. Kiyohara, Alpha-N-acetylgalactosaminidase from infant-associated bifidobacteria belonging to novel glycoside hydrolase family 129 is implicated in alternative mucin degradation pathway, J. Biol. Chem, vol.287, pp.693-700, 2012.

Z. A. Popper, Evolution and diversity of plant cell walls: from algae to flowering plants, Annu. Rev. Plant Biol, vol.62, pp.567-590, 2011.
URL : https://hal.archives-ouvertes.fr/hal-01117618

G. Correc, Comparison of the structures of hybrid ?-/?-carrageenans extracted from Furcellaria lumbricalis and Tichocarpus crinitus, Carbohydr. Polym, vol.88, pp.31-36, 2012.
URL : https://hal.archives-ouvertes.fr/hal-02108474

P. Jackson, The use of polyacrylamide-gel electrophoresis for the highresolution separation of reducing saccharides labelled with the fluorophore 8aminonaphthalene-1,3,6-trisulphonic acid. Detection of picomolar quantities by an imaging system based on a cooled charge-coupled device, Biochem. J, vol.270, pp.705-713, 1990.

E. J. Yun, The novel catabolic pathway of 3,6-anhydro-L-galactose, the main component of red macroalgae, in a marine bacterium, Environ. Microbiol, vol.17, pp.1677-1688, 2015.

S. B. Lee, J. A. Kim, and H. S. Lim, Metabolic pathway of 3,6-anhydro-Dgalactose in carrageenan-degrading microorganisms, Appl. Microbiol. Biotechnol, vol.100, pp.4109-4121, 2016.

M. W. Vetting, J. T. Bouvier, J. A. Gerlt, and S. C. Almo, Purification, crystallization and structural elucidation of D-galactaro-1,4-lactone cycloisomerase from Agrobacterium tumefaciens involved in pectin degradation, Acta. Crystallogr. Sect. F Struct. Biol. Cryst. Commun, vol.72, pp.36-41, 2016.

Y. Zhu, Genetic analyses unravel the crucial role of a horizontally acquired alginate lyase for brown algal biomass degradation by Zobellia galactanivorans, Environ. Microbiol, vol.19, pp.2164-2181, 2017.

J. H. Hehemann, Biochemical and structural characterization of the complex agarolytic enzyme system from the marine bacterium Zobellia galactanivorans, J. Biol. Chem, vol.287, pp.30571-30584, 2012.
URL : https://hal.archives-ouvertes.fr/hal-02108464

M. Reher, T. Fuhrer, M. Bott, and P. Schonheit, The nonphosphorylative Entner-Doudoroff pathway in the thermoacidophilic euryarchaeon Picrophilus torridus involves a novel 2-keto-3-deoxygluconate-specific aldolase, J. Bacteriol, vol.192, pp.964-974, 2010.

S. Blanvillain, Plant carbohydrate scavenging through tonB-dependent receptors: a feature shared by phytopathogenic and aquatic bacteria, PLoS ONE, vol.2, p.224, 2007.

J. H. Hehemann, Transfer of carbohydrate-active enzymes from marine bacteria to Japanese gut microbiota, Nature, vol.464, pp.908-912, 2010.

E. Rebuffet, Discovery and structural characterization of a novel glycosidase family of marine origin, Environ. Microbiol, vol.13, pp.1253-1270, 2011.

J. M. Grondin, K. Tamura, G. Dejean, D. W. Abbott, and H. Brumer, Polysaccharide utilization loci: fuelling microbial communities, J. Bacteriol

A. Groisillier, MARINE-EXPRESS: taking advantage of high throughput cloning and expression strategies for the post-genomic analysis of marine organisms, Microb. Cell Fact, vol.9, p.45, 2010.
URL : https://hal.archives-ouvertes.fr/hal-00609166

F. W. Studier, Protein production by auto-induction in high density shaking cultures, Protein Expr. Purif, vol.41, pp.207-234, 2005.

E. Ficko-blean, Biochemical and structural investigation of two paralogous glycoside hydrolases from Zobellia galactanivorans: novel insights into the evolution, dimerization plasticity and catalytic mechanism of the GH117 family, Acta Crystallogr. D, vol.71, pp.209-223, 2015.
URL : https://hal.archives-ouvertes.fr/hal-01140143

E. Gasteiger, Protein identification and analysis tools on the ExPASy Server, The Proteomics Protocols Handbook, 2005.

G. Michel, Expression, purification, crystallization and preliminary x-ray analysis of the kappa-carrageenase from Pseudoalteromonas carrageenovora, Acta Crystallogr. D, vol.55, pp.918-920, 1999.

G. Michel, Expression, purification, crystallization and preliminary X-ray analysis of the iota-carrageenase from Alteromonas fortis, Acta Crystallogr. D, vol.56, pp.766-768, 2000.

C. L. Buchanan, H. Connaris, M. J. Danson, C. D. Reeve, and D. W. Hough, An extremely thermostable aldolase from Sulfolobus solfataricus with specificity for non-phosphorylated substrates, Biochem. J, vol.343, pp.563-570, 1999.

H. R. Powell, The Rossmann Fourier autoindexing algorithm in MOSFLM, Acta Crystallogr. D, vol.55, pp.1690-1695, 1999.
DOI : 10.1107/s0907444999009506

URL : http://journals.iucr.org/d/issues/1999/10/00/ba0024/ba0024.pdf

A. G. Leslie, Recent changes to the MOSFLM package for processing film and image plate data, Jnt. CCP4/ESF-EACBM Newslett. Protein Crystallogr, vol.26, 1992.

P. R. Evans, An introduction to data reduction: space-group determination, scaling and intensity statistics, Acta Crystallogr. D, vol.67, pp.282-292, 2011.
DOI : 10.1107/s090744491003982x

URL : http://journals.iucr.org/d/issues/2011/04/00/ba5158/ba5158.pdf

P. Evans, Scaling and assessment of data quality, Acta Crystallogr. D, vol.62, pp.72-82, 2006.

, Collaborative Computational Project Number 4. The CCP4 suite: programs for protein crystallography, Acta Crystallogr. D, vol.50, pp.760-763, 1994.

T. R. Schneider and G. M. Sheldrick, Substructure solution with SHELXD, Acta Crystallogr. D, vol.58, pp.1772-1779, 2002.

S. R. Ness, R. A. De-graaff, J. P. Abrahams, and N. S. Pannu, CRANK: new methods for automated macromolecular crystal structure solution, Structure, vol.12, pp.1753-1761, 2004.
DOI : 10.1107/s0108767304099702

URL : http://journals.iucr.org/a/issues/2004/a1/00/a31223/a31223.pdf

A. Vagin and A. Teplyakov, MOLREP: an automated program for molecular replacement, J. Appl. Crystallogr, vol.30, pp.1022-1025, 1997.
DOI : 10.1107/s0021889897006766

A. A. Vagin, REFMAC5 dictionary: organization of prior chemical knowledge and guidelines for its use, Acta Crystallogr. D, vol.60, pp.2184-2195, 2004.

P. Emsley, B. Lohkamp, W. G. Scott, and K. Cowtan, Features and development of Coot, Acta Crystallogr. D, vol.66, pp.486-501, 2010.

W. Kabsch and . Xds, Acta Crystallogr. D, vol.66, pp.125-132, 2010.

W. Kabsch, Integration, scaling, space-group assignment and post-refinement, Acta Crystallogr. D, vol.66, pp.133-144, 2010.
DOI : 10.1107/s0907444909047374

URL : http://journals.iucr.org/d/issues/2010/02/00/dz5178/dz5178.pdf

A. J. Mccoy, Phaser crystallographic software, J. Appl. Crystallogr, vol.40, pp.658-674, 2007.

O. S. Smart, Exploiting structure similarity in refinement: automated NCS and target-structure restraints in BUSTER, Acta Crystallogr. D, vol.68, pp.368-380, 2012.

D. Ropartz, Performance evaluation on a wide set of matrix-assisted laser desorption ionization matrices for the detection of oligosaccharides in a highthroughput mass spectrometric screening of carbohydrate depolymerizing enzymes, Rapid Commun. Mass. Spectrom, vol.25, pp.2059-2070, 2011.
URL : https://hal.archives-ouvertes.fr/hal-01967556

C. Zobell, Studies on marine bacteria I The cultural requirements of heterotrophic aerobes, J Mar Res, vol.4, pp.42-75, 1941.

F. Thomas, T. Barbeyron, and G. Michel, Evaluation of reference genes for realtime quantitative PCR in the marine flavobacterium Zobellia galactanivorans, J. Microbiol. Methods, vol.84, pp.61-66, 2011.

R. Schmieder and R. Edwards, Quality control and preprocessing of metagenomic datasets, Bioinformatics, vol.27, pp.863-864, 2011.
DOI : 10.1093/bioinformatics/btr026

URL : https://academic.oup.com/bioinformatics/article-pdf/27/6/863/646767/btr026.pdf

B. Langmead and S. L. Salzberg, Fast gapped-read alignment with Bowtie 2, Nat. Methods, vol.9, pp.357-359, 2012.
DOI : 10.1038/nmeth.1923

URL : http://europepmc.org/articles/pmc3322381?pdf=render

H. Li, The sequence alignment/map format and SAMtools, Bioinformatics, vol.25, pp.2078-2079, 2009.
DOI : 10.1093/bioinformatics/btp352

URL : https://academic.oup.com/bioinformatics/article-pdf/25/16/2078/531810/btp352.pdf

C. Toffano-nioche, Transcriptomic profiling of the oyster pathogen Vibrio splendidus opens a window on the evolutionary dynamics of the small RNA repertoire in the Vibrio genus, RNA, vol.18, pp.2201-2219, 2012.
URL : https://hal.archives-ouvertes.fr/hal-00757205

K. Rutherford, Artemis: sequence visualization and annotation, Bioinformatics, vol.16, pp.944-945, 2000.
DOI : 10.1093/bioinformatics/16.10.944

URL : https://academic.oup.com/bioinformatics/article-pdf/16/10/944/598346/160944.pdf

S. Anders, P. T. Pyl, and W. Huber, HTSeq-a Python framework to work with high-throughput sequencing data, Bioinformatics, vol.31, pp.166-1669, 2015.
DOI : 10.1093/bioinformatics/btu638

URL : https://academic.oup.com/bioinformatics/article-pdf/31/2/166/7000027/btu638.pdf

H. Varet, L. Brillet-gueguen, J. Y. Coppee, and M. A. Dillies, SARTools: A DESeq2-and Edger-based R pipeline for comprehensive differential analysis of RNA-Seq data, PLoS ONE, vol.11, p.157022, 2016.
URL : https://hal.archives-ouvertes.fr/hal-01344179

D. Vallenet, MicroScope in 2017: an expanding and evolving integrated resource for community expertise of microbial genomes, Nucleic Acids Res, vol.45, pp.517-528, 2016.

K. Katoh and D. M. Standley, MAFFT multiple sequence alignment software version 7: improvements in performance and usability, Mol. Biol. Evol, vol.30, pp.772-780, 2013.
DOI : 10.1093/molbev/mst010

URL : https://academic.oup.com/mbe/article-pdf/30/4/772/6420419/mst010.pdf

A. Criscuolo, S. Gribaldo, and . Bmge, Block Mapping and Gathering with Entropy): a new software for selection of phylogenetic informative regions from multiple sequence alignments, BMC Evol. Biol, vol.10, p.210, 2010.

D. Darriba, G. L. Taboada, R. Doallo, and D. Posada, ProtTest 3: fast selection of best-fit models of protein evolution, Bioinformatics, vol.27, pp.1164-1165, 2011.

S. Guindon, New algorithms and methods to estimate maximumlikelihood phylogenies: assessing the performance of PhyML 3.0, Syst. Biol, vol.59, pp.307-321, 2010.
URL : https://hal.archives-ouvertes.fr/lirmm-00511784

I. Letunic and P. Bork, Interactive tree of life (iTOL) v3: an online tool for the display and annotation of phylogenetic and other trees, Nucleic Acids Res, vol.44, pp.242-245, 2016.

E. F. -b-;-a, R. L. , R. L. , Y. T. , T. B. et al., performed the mass spectrometry experiments. G.C. produced and purified the furcellaran oligosaccharides. M.M. performed the site-directed mutagenesis of ZGAL_3152. K.A.S. synthesized initial potential substrates for ZGAL_3152 and