Table S1. Response regulators encoded in bacterial and archaeal genomesa

A web supplement to the paper "Structural classification of bacterial response regulators:
Diversity of output domains and domain combinations
" by Michael Y. Galperin,
published in the Journal of Bacteriology (2006) 188: 4169-4182. Abstract in PubMed.
Free full text (HTML). Free full text (PDF). PDF from PubMed Central. Request reprint.

Additional links:
TM0468, query sequence for PSI-BLAST searches
PSSM for PSI-BLAST searches using TM0468 as a query

Organism GenBank
entry
No. genes Stand-
alone
REC
DNA-binding RNA Enzymatic CheV Other
RRs
All
RRs
Actinobacteria OmpR NarL NtrC LytR PrrA AraC AmiR GGDEF/
EAL
RpfG HisK PP2C CheB
Bifidobacterium longum AE014295 1727 - 5 4 - - - - 1 - - - - - - - 10
Corynebacterium diphtheriae BX248353 2272 - 6 5 - - - - - - - - - - - - 11
Corynebacterium efficiens BA000035 2950 - 6 7 - - - - - - - - - - - - 13
Corynebacterium glutamicum BA000036 2993 - 8 6 - - - - - - - - - - - - 14
Corynebacterium jeikeium CR931997 2137 - 6 3 - - - - - - - - - - - - 9
Leifsonia xyli AE016822 2030 1 7 11 - - - - 1 - - - - - - 1 21
Mycobacterium avium subsp. paratuberculosis AE016958 4350 2 10 4 - - - - 1 - - - - - - 1 18
Mycobacterium bovis BX248333 3920 - 9 2 - - - - 1 - - - - - - - 12
Mycobacterium leprae AL450380 1605 - 4 - - - - - 1 - - - - - - - 5
Mycobacterium tuberculosis H37Rv AL123456 3927 1 9 2 - - - - 1 - - - - - - - 13
Nocardia farcinica AP006618 5936 2 10 17 - 1 - - 1 - - - 1 - - 1 33
Propionibacterium acnes AE017283 2297 1 5 6 - - - - 1 - - - - - - - 13
Streptomyces avermitilis BA000030 7671 3 26 35 - 1 - - 1 - - - 3 - - 1 70
Streptomyces coelicolor AL645882 8154 3 21 53 - 1 - - 1 - - - 2 - - 3 84
Symbiobacterium thermophilum AP006840 3337 5 10 11 2 1 - - 1 1 - - - 1 - 2 34
Thermobifida fusca CP000088 3110 2 8 13 - 1 - - 1 - - - 1 - - 2 28
Tropheryma whipplei BX072543 783 - 1 1 - - - - - - - - - - - - 2
Cyanobacteria GenBank Genes REC OmpR NarL NtrC LytR PrrA AraC AmiR GGDEF/
EAL
RpfG HisK PP2C CheB CheV Other All
Anabaena variabilis CP000117 5657 21 14 16 - - - 1 - 5 1 14 3 - - 13 88
Gloeobacter violaceus BA000045 4430 7 10 15 - - - - - - - 1 - - - 6 39
Nostoc sp. PCC 7120 BA000019 6055 24 15 17 - - - 2 - 6 1 15 4 - - 12 96
Prochlorococcus marinus CCMP1375 AE017126 1882 - 4 2 - - - - - - - - - - - - 6
Synechococcus elongatus PCC 6301 AP008231 2525 5 8 1 - - - - - 2 - - - - - 3 19
Synechococcus sp. WH 8102 BX548020 2517 - 6 3 - - - - - - - - - - - - 9
Synechocystis sp. PCC 6803 BA000022 3567 7 10 7 - - - 1 - 5 2 5 1 - - 9 47
Thermosynechococcus elongatus BA000039 2475 4 7 4 - - - - - 2 - - 1 - - 6 24
Alpha-proteobacteria GenBank Genes REC OmpR NarL NtrC LytR PrrA AraC AmiR GGDEF/
EAL
RpfG HisK PP2C CheB CheV Other All
Agrobacterium tumefaciens AE008688 5402 14 22 8 5 - 1 - 1 2 - 1 - 1 - 3 58
Anaplasma marginale CP000030 949 - 1 - 1 - - - - 1 - - - - - - 3
Bartonella henselae BX897699 1488 2 6 - 2 - - - - - - - - - - 1 11
Bartonella quintana BX897700 1142 2 6 - 2 - - - - - - - - - - 1 11
Bradyrhizobium japonicum BA000040 8317 30 22 23 5 - 2 - 1 2 2 2 - 2 - 5 96
Brucella abortus AE017223 3085 3 10 3 3 - 1 - - 1 - - - - - 1 22
Brucella melitensis 16M AE008917 3198 3 10 3 3 - 1 - - 1 - - - - - 1 22
Brucella suis 1330 AE014291 3271 3 10 3 3 - 1 - - 1 - - - - - 1 22
Caulobacter crescentus AE005673 3737 14 12 2 4 - 2 - 1 2 - - - 2 - 6 45
Ehrlichia canis CP000107 925 - 1 - 1 - - - - 1 - - - - - - 3
Ehrlichia ruminantium CR767821 888 - 1 - 1 - - - - 1 - - - - - - 3
Gluconobacter oxydans CP000009 2664 6 9 1 1 - - - - - - 2 - 1 - 1 21
Mesorhizobium loti BA000012 7275 12 23 10 5 - 2 - 1 2 - 2 - 1 - 1 59
Nitrobacter winogradskyi CP000115 3122 8 8 3 3 - 1 - - 2 - 1 - 1 - 2 29
Pelagibacter ubique CP000084 1354 - 3 - 1 - 1 - - - - - - - - - 5
Rhodopseudomonas palustris BX571963 4813 18 11 8 4 - 1 - 1 2 2 2 - 2 - 3 54
Rickettsia conorii AE006914 1374 - 2 - 1 - - - - 1 - - - - - - 4
Rickettsia felis CP000053 1532 - 2 - 1 - - - - 1 - - - - - - 4
Rickettsia prowazekii AJ235269 835 - 2 - 1 - - - - 1 - - - - - - 4
Rickettsia typhi AE017197 838 - 2 - 1 - - - - 1 - - - - - - 4
Silicibacter pomeroyi CP000031 4252 2 9 5 5 - 1 - - 1 - - 1 - - 2 26
Sinorhizobium meliloti AL591688 6205 15 16 12 5 1 1 - 1 1 - - - 2 - 3 57
Wolbachia endosymbiont of Brugia malayi AE017321 805 - 1 - - - - - - 1 - - - - - - 2
Wolbachia endosymbiont of Drosophila AE017196 1195 - 1 - - - - - - 1 - - - - - - 2
Zymomonas mobilis AE008692 1998 2 6 - 1 1 - - - - - - - 2 - 1 13
Beta-proteobacteria GenBank Genes REC OmpR NarL NtrC LytR PrrA AraC AmiR GGDEF/
EAL
RpfG HisK PP2C CheB CheV Other All
Azoarcus sp. EbN1 CR555306 4609 6 11 13 10 1 - - - 5 - - - - - 1 47
Bordetella bronchiseptica BX470250 4994 2 18 7 2 - 2 - - 1 - - - 1 - - 33
Bordetella parapertussis BX470249 4185 2 16 5 2 - 2 - - 1 - - - 1 - - 29
Bordetella pertussis BX470248 3436 1 13 4 1 - 2 - - - - - - 1 - - 22
Burkholderia mallei CP000011 4764 6 14 5 5 - 2 - 1 - 2 1 - 1 - 1 38
Burkholderia pseudomallei BX571965 5728 3 15 11 1 - 2 - - - 1 1 - 1 - 3 38
Chromobacterium violaceum AE016825 4407 6 10 7 5 4 1 - 1 9 5 - 2 3 3 9 65
Dechloromonas aromatica CP000089 4171 16 17 12 14 2 1 - 1 12 7 2 1 2 2 9 98
Neisseria gonorrhoeae AE004969 2002 - 1 - 1 - - - - - - - - - - - 2
Neisseria meningitidis AE002098 2079 - 1 1 1 - 1 - - - - - - - - 1 5
Nitrosomonas europaea AL954747 2461 3 7 - 4 - 1 - - 3 - - - 1 - - 19
Ralstonia eutropha CP000090 6446 7 22 17 5 1 2 - 1 1 1 2 - 2 1 6 68
Ralstonia solanacearum AL646052 5116 7 27 14 5 1 2 - 1 1 - 1 - 1 1 3 64
Thiobacillus denitrificans CP000116 2827 5 7 8 7 1 1 - 1 5 1 - - 1 1 - 38
Delta-proteobacteria GenBank Genes REC OmpR NarL NtrC LytR PrrA AraC AmiR GGDEF/
EAL
RpfG HisK PP2C CheB CheV Other All
Bdellovibrio bacteriovorus BX842601 3587 13 9 2 6 - 1 - - 1 - 1 - 2 - 6 41
Desulfotalea psychrophila CR522870 3234 5 3 1 11 - - - - 2 3 - - 2 - 4 31
Desulfovibrio vulgaris AE017285 3531 20 2 3 23 2 - - - 2 5 4 1 2 3 9 76
Geobacter sulfurreducens AE017180 3446 23 7 4 26 - - - 1 10 4 2 1 3 1 9 91
Epsilon-proteobacteria GenBank Genes REC OmpR NarL NtrC LytR PrrA AraC AmiR GGDEF/
EAL
RpfG HisK PP2C CheB CheV Other All
Campylobacter jejuni AL111168 1634 1 6 - 1 - - - - 1 - 1 - - 1 1 12
Helicobacter hepaticus AE017125 1875 1 3 - 1 - - - - - - - - - 3 2 10
Helicobacter pylori AE000511 1576 1 3 - 1 - - - - - - - - - 3 1 9
Wolinella succinogenes BX571656 2044 3 20 - 1 - - - - 4 1 4 2 - 4 9 48
Gamma-proteobacteria GenBank Genes REC OmpR NarL NtrC LytR PrrA AraC AmiR GGDEF/
EAL
RpfG HisK PP2C CheB CheV Other All
Acinetobacter sp. ADP1 CR543861 3325 2 9 2 3 1 - - 1 - - - - - - - 18
Blochmannia floridanus BX248583 583 - - - - - - - - - - - - - - - 0
Blochmannia pennsylvanicus CP000016 610 - - - - - - - - - - - - - - - 0
Buchnera aphidicola BA000003 574 - - - - - - - - - - - - - - - 0
Colwellia psychrerythraea CP000083 4910 5 22 8 11 3 1 - 1 5 2 1 - 1 1 6 67
Coxiella burnetii AE016828 2046 1 3 4 - - - - - - - - - - - - 8
Erwinia carotovora BX950851 4472 1 12 8 2 2 - - - - - - - 1 1 1 28
Escherichia coli K12 U00096 4242 1 14 9 4 2 - - - - - - - 1 - 1 32
Escherichia coli O157:H7 BA000007 5253 1 15 10 3 2 - - - - - - - 1 - 1 33
Francisella tularensis AJ749949 1804 - 2 - - - - - - - - - - - - - 2
Haemophilus ducreyi AE017143 1717 - 2 1 - - - - - - - - - - - - 3
Haemophilus influenzae L42023 1711 - 4 1 - - - - - - - - - - - 1 6
Idiomarina loihiensis AE017340 2640 4 7 5 4 2 1 - - 1 2 - 1 1 1 2 31
Legionella pneumophila AE017354 2942 3 3 2 2 - - - - 1 - - - - - 2 13
Mannheimia succiniciproducens AE016827 2384 - 3 2 - - - - - - - - - - - - 5
Methylococcus capsulatus AE017282 2959 2 7 2 4 - 1 - 1 2 - - 2 1 - - 22
Pasteurella multocida AE004439 2015 - 5 3 1 - - - - - - - - - - - 9
Photobacterium profundum CR354531 5480 6 20 8 7 3 - - - 4 - 1 - 2 2 6 59
Photorhabdus luminescens BX470251 4683 1 7 7 2 1 - - - - - - - 1 - 1 20
Pseudomonas aeruginosa AE004091 5567 6 24 16 8 1 1 - 1 5 2 - 2 4 1 2 73
Pseudomonas fluorescens CP000076 6137 11 29 18 9 1 1 - - 7 3 2 2 2 3 4 92
Pseudomonas putida AE015451 5350 11 25 11 8 1 1 - 1 3 1 2 2 2 3 4 75
Pseudomonas syringae AE016853 5608 11 19 12 8 1 1 - 1 5 - 1 2 3 3 4 71
Psychrobacter arcticum CP000082 2120 3 7 3 1 - - - - - - - - - - - 14
Salmonella enterica subsp. enterica serovar Paratyphi CP000026 4093 1 13 11 4 1 - - - - - - - 1 1 1 33
Salmonella enterica subsp. enterica serovar Typhi AL513382 4758 1 12 11 4 1 - - - - - - - 1 1 1 32
Salmonella typhimurium LT2 AE006468 4527 1 13 11 4 1 - - - - - - - 1 1 1 33
Shewanella oneidensis AE014299 4467 5 18 8 5 1 1 - - 3 4 1 1 3 3 4 57
Shigella flexneri AE005674 4441 2 13 5 3 2 - - - - - - - 1 - 1 27
Shigella sonnei CP000038 4461 1 14 8 4 2 - - - - - - - 1 - 1 31
Vibrio cholerae AE003852 3835 6 12 6 7 2 - - - 2 3 - 1 2 4 4 49
Vibrio fischeri CP000020 3802 2 13 5 5 2 - - - 2 - - 1 1 3 5 39
Vibrio parahaemolyticus BA000031 4832 3 16 11 10 2 - - - 2 - - 1 1 4 5 55
Vibrio vulnificus AE016795 5024 4 12 10 9 2 - - - 6 3 - 1 2 4 7 60
Wigglesworthia glossinidia BA000021 617 - 1 - - - - - - - - - - - - - 1
Xanthomonas axonopodis AE008923 4427 14 11 10 4 3 1 - - 5 2 1 - 2 1 3 57
Xanthomonas campestris AE008922 4181 16 11 8 5 2 1 - 1 5 2 1 - 2 1 2 57
Xanthomonas oryzae AE013598 4637 12 12 5 4 1 1 - - 5 2 1 - 2 1 4 50
Xylella fastidiosa 9a5c AE003849 2832 4 5 2 2 1 1 - - 1 1 1 - - - 1 19
Yersinia pestis AL590842 4067 - 6 1 1 1 - - - - - - - 1 - 1 11
Yersinia pseudotuberculosis BX936398 4038 1 14 7 3 1 - - - - - - - 1 - 1 28
Firmicutes GenBank Genes REC OmpR NarL NtrC LytR PrrA AraC AmiR GGDEF/
EAL
RpfG HisK PP2C CheB CheV Other All
Bacillus anthracis str. Ames AE016879 5311 4 31 8 - 3 - - - - - - 1 - - 3 50
Bacillus cereus ATCC 14579 AE016877 5255 2 28 9 - 2 - - - - - - 1 - 1 3 46
Bacillus clausii AP006627 4096 2 15 13 1 1 - 6 - - - - - - 1 2 41
Bacillus halodurans BA000004 4066 4 16 10 2 - - 7 - 2 - - - 1 2 4 48
Bacillus licheniformis AE017333 4196 4 11 14 - 1 - 2 - - - - - 1 1 3 37
Bacillus subtilis AL009126 4105 3 13 12 - 2 - 1 - - - - - 1 1 2 35
Bacillus thuringiensis serovar konkukian AE017355 5117 2 30 10 - 3 - 1 - - - - 1 - 1 3 51
Clostridium acetobutylicum AE001437 3848 4 21 7 - 3 - - 1 - - - - 1 1 5 43
Clostridium perfringens BA000016 2723 1 13 1 - 2 - 3 1 - - - - - - - 21
Clostridium tetani AE015927 2442 2 20 1 1 2 - 2 1 - - - - - - 1 30
Enterococcus faecalis AE016830 3265 - 11 2 - 3 - 1 1 - - - - - - - 18
Geobacillus kaustophilus BA000043 3540 3 10 5 1 1 - 5 - 1 - - - 1 - 2 29
Lactobacillus acidophilus CP000033 1864 - 6 2 - - - - - - - - - - - - 8
Lactobacillus johnsonii AE017198 1821 - 6 1 - 2 - - - - - - - - - - 9
Lactobacillus plantarum AL935263 3059 - 6 2 - 6 - 1 - - - - - - - - 15
Lactococcus lactis AE005176 2321 - 6 1 - - - - - - - - - - - - 7
Listeria innocua AL592022 2968 1 10 2 - 2 - 1 1 - - - - - 1 - 18
Listeria monocytogenes AL591824 2846 - 9 1 - 1 - 1 1 - - - - - 1 - 14
Mesoplasma florum AE017263 682 - - - - - - - - - - - - - - - 0
Mycoplasma gallisepticum AE015450 726 - - - - - - - - - - - - - - - 0
Mycoplasma genitalium L43967 484 - - - - - - - - - - - - - - - 0
Mycoplasma hyopneumoniae AE017332 691 - - - - - - - - - - - - - - - 0
Mycoplasma mobile AE017308 633 - - - - - - - - - - - - - - - 0
Mycoplasma mycoides BX293980 1016 - - - - - - - - - - - - - - - 0
Mycoplasma penetrans BA000026 1037 - - - - - - - - - - - - - - - 0
Mycoplasma pneumoniae U00089 689 - - - - - - - - - - - - - - - 0
Mycoplasma pulmonis AL445566 782 - - - - - - - - - - - - - - - 0
Mycoplasma synoviae AE017245 672 - - - - - - - - - - - - - - - 0
Oceanobacillus iheyensis BA000028 3500 2 8 7 - 1 - 1 - - - - - 1 - 1 21
Onion yellows phytoplasma AP006628 754 - - - - - - - - - - - - - - - 0
Staphylococcus aureus BA000018 2624 1 9 4 - 2 - 1 - - - - - - - - 17
Staphylococcus epidermidis AE015929 2419 - 9 4 - 2 - 1 - - - - - - - - 16
Staphylococcus haemolyticus AP006716 2676 - 9 4 - 2 - - - - - - - - - - 15
Staphylococcus saprophyticus AP008934 2514 - 6 3 - 2 - - - - - - - - - - 11
Streptococcus agalactiae AE009948 2124 - 13 2 - 3 - 1 - - - - - - - 1 20
Streptococcus mutans AE014133 1960 - 9 3 - 2 - - - - - - - - - - 14
Streptococcus pneumoniae AE005672 2094 - 8 2 - 2 - 2 - - - - - - - - 14
Streptococcus pyogenes M1 GAS AE004092 1697 - 5 3 - 1 - 3 - - - - - - - - 12
Streptococcus thermophilus CP000024 1915 1 4 2 - 2 - - - - - - - - - - 9
Thermoanaerobacter tengcongensis AE008691 2588 3 7 1 - 2 - 2 - 3 - - - 1 - 2 21
Ureaplasma parvum AF222894 614 - - - - - - - - - - - - - - - 0
Other bacterial phyla GenBank Genes REC OmpR NarL NtrC LytR PrrA AraC AmiR GGDEF/
EAL
RpfG HisK PP2C CheB CheV Other All
CFB/ green sulfur bacteria                                    
Bacteroides fragilis AP006841 4625 2 8 2 8 6 - 1 - - - 1 1 - - - 29
Bacteroides thetaiotaomicron AE015928 4816 2 6 - 8 10 - - - - - 1 - - - - 27
Chlorobium tepidum AE006470 2252 2 2 - - - - - - - - - - - - - 4
Porphyromonas gingivalis AE015924 1909 - 2 1 2 - - - - - - - - - - 1 6
Chlamydiae                                    
Chlamydia muridarum AE002160 904 - 1 - 1 - - - - - - - - - - - 2
Chlamydia trachomatis AE001273 895 - 1 - 1 - - - - - - - - - - - 2
Chlamydophila abortus CR848038 932 - 1 - 1 - - - - - - - - - - - 2
Chlamydophila caviae AE015925 1005 - 1 - 1 - - - - - - - - - - - 2
Chlamydophila pneumoniae AE001363 1054 - 1 - 1 - - - - - - - - - - - 2
Parachlamydia sp. UWE25 BX908798 2031 - 1 - 1 - - - - - - - - - - - 2
Deinococcus/ Thermus                                    
Deinococcus radiodurans AE000513 3184 8 8 6 - - - - - - - 2 - - - 2 26
Thermus thermophilus AE017221 2210 3 7 3 - - - - - - 1 - - - - - 14
Spirochaetes                                    
Borrelia burgdorferi AE001115 1639 2 - - 1 - - - - 1 - - - 1 - - 5
Borrelia garinii CP000013 932 3 - - 1 - - - - 1 - - - 1 - - 6
Leptospira interrogans serovar lai AE010300 4727 14 5 3 1 - - - - 4 - 4 2 2 - 3 38
Treponema denticola AE017226 2767 2 1 2 1 1 - - - - - 1 - 1 - 2 11
Treponema pallidum AE000520 1036 1 - - 1 - - - - - - - - 1 - - 3
Other                                     
Aquifex aeolicus AE000657 1560 1 1 - 3 - - - - - - - - - - - 5
Dehalococcoides ethenogenes CP000027 1580 2 14 8 - - - - - - 1 - - - - 1 26
Dehalococcoides sp. CBDB1 AJ965256 1458 2 18 7 - - - - - - 2 - - - - 1 30
Fusobacterium nucleatum  AE009951 2066 - 2 1 2 1 - 1 1 - - - - - - - 8
Rhodopirellula baltica BX119912 7325 22 4 4 10 - 1 - 1 4 1 1 - - - 10 58
Thermotoga maritima AE000512 1858 3 4 - - - - - - 2 2 - - 1 - - 12
Archaea GenBank Genes REC OmpR NarL NtrC LytR PrrA AraC AmiR GGDEF/
EAL
RpfG HisK PP2C CheB CheV Other All
Aeropyrum pernix BA000002 1841 - - - - - - - - - - - - - - - 0
Archaeoglobus fulgidus AE000782 2420 9 - - - - - - - - - - - 1 - - 10
Haloarcula marismortui AY596297 4240 7 - - - - - - - - - 1 - 1 - 16 25
Halobacterium sp. NRC-1 AE004437 2622 1 - - - - - - - - - - - 1 - 3 5
Methanocaldococcus jannaschii L77117 1786 - - - - - - - - - - - - - - - 0
Methanococcus maripaludis BX950229 1722 2 - - - - - - - - - - - 1 - - 3
Methanopyrus kandleri AE009439 1687 - - - - - - - - - - - - - - - 0
Methanosarcina acetivorans AE010299 4540 12 - - - - - - - - - - - 2 - 1 15
Methanosarcina barkeri CP000099 3625 9 - - - - - - - - - - - 1 - 1 11
Methanosarcina mazei AE008384 3371 11 - - - - - - - - - - - 2 - 1 14
Methanothermobacter thermautotrophicus AE000666 1873 1 - - - - - - - - - 1 - - - 6 8
Nanoarchaeum equitans AE017199 535 - - - - - - - - - - - - - - - 0
Picrophilus torridus AE017261 1535 - - - - - - - - - - - - - - - 0
Pyrobaculum aerophilum AE009441 2605 - - - - - - - - - - - - - - - 0
Pyrococcus abyssi AL096836 1896 1 - - - - - - - - - - - 1 - - 2
Pyrococcus furiosus AE009950 2125 - - - - - - - - - - - - - - - 0
Pyrococcus horikoshii BA000001 1955 1 - - - - - - - - - - - 1 - - 2
Sulfolobus acidocaldarius CP000077 2223 - - - - - - - - - - - - - - - 0
Sulfolobus solfataricus AE006641 2977 - - - - - - - - - - - - - - - 0
Sulfolobus tokodaii BA000023 2825 - - - - - - - - - - - - - - - 0
Thermococcus kodakarensis AP006878 2306 1 - - - - - - - - - - - 1 - - 2
Thermoplasma acidophilum AL139299 1481 - - - - - - - - - - - - - - - 0
Thermoplasma volcanium BA000011 1499 - - - - - - - - - - - - - - - 0
Organism GenBank Genes REC OmpR NarL NtrC LytR PrrA AraC AmiR GGDEF/
EAL
RpfG HisK PP2C CheB CheV Other All
Total number     659 1526 862 393 139 48 48 40 187 72 88 46 107 72 323 4610
Percent total     14.3% 33.1% 18.7% 8.5% 3.0% 1.0% 1.0% 0.9% 4.1% 1.6% 1.9% 1.0% 2.3% 1.6% 7.0% 100.0%

a Within each group, the organisms are sorted in the alphabetical order. The numbers in the table are linked to phylum-specific lists of response regulators, which are further linked to RefSeq and UniProt entries, BLink outputs, and CDD and Pfam domain architectures. The numbers in the "Total number" line are linked to lists of specific types of response regulators in all studied organisms, where available.


Please send corrections, questions and comments to Michael Galperin